St. Louis city, MO Building Permits & Zoning

St. Louis city, Missouri requires a building permit for new construction, structural changes and major alterations; normal maintenance usually does not need one¹. The city enforces adopted building codes and zoning throughout its jurisdiction²³. Apply through the Building Division, and expect zoning review, inspections and an occupancy approval before moving into a residential unit⁴⁵.

At a glance

Building permit: Required for new construction, structural changes and major alterations¹
Zoning: Citywide; the parcel's district and overlays control uses and dimensions³⁶
Septic: Public sewer is standard; confirm the authority before proposing an onsite system⁷
Homeowner electrical work: Conditional for limited work in an owner-occupied single-family home; not new construction⁸
Residential occupancy: Inspection and a Certificate of Inspection are required before occupancy⁹
Accessory dwelling: One attached or detached ADU may be permitted in residential zoning districts¹⁰

Who to call

Building permits

City of St. Louis Building Division

Enforces the city building code, issues building permits, conducts inspections, and enforces zoning ordinances citywide

(314) 622-3313

dps-building-division@stlouis-mo.gov

1200 Market Street, City Hall, Room 426, St. Louis, Missouri 63103-2826

Online permits →

Zoning

City of St. Louis Zoning Section

Administers and enforces the City of St. Louis Zoning Code Ordinance (Title 26); reviews building and occupancy permits for zoning compliance

(314) 622-3666

zoning@stlouis-mo.gov

1200 Market Street, Room 400, St. Louis, Missouri 63103

Online permits →

Zoning

City of St. Louis Zoning Section — Zoning FAQ

The Zoning Section's own published answers on setbacks, building lines, and lot lines

Septic permits

Metropolitan St. Louis Sewer District (MSD) Customer Service

Public sanitary sewer service and connections for St. Louis city; the practical alternative to septic here

(314) 768-6260

2350 Market Street, St. Louis, MO 63103-2555

Contact details are copied from each office’s official page and were checked against it on October 10, 2026.

Off-grid gear

Going off-grid in St. Louis City means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in St. Louis city, Missouri?

Yes. St. Louis city requires a building permit for new construction, structural changes and major alterations, while normal building maintenance usually does not require one¹. The city has adopted building, residential, energy, fire, plumbing, mechanical, fuel-gas, electrical, existing-building and property-maintenance codes². Separate plumbing, mechanical or electrical permits may also apply¹¹.

A homeowner may obtain an electrical permit only after passing the Building Division's knowledge test and only for a room addition, repair or modification to the existing system in an owner-occupied single-family dwelling⁸. Service changes, rehabilitation and new construction electrical work must be performed by a licensed contractor⁸. The city does not state a broader owner-builder exemption for general residential construction, so ask the Building Division who may pull each required permit before choosing contractors¹².

Who is the St. Louis city building department, and how do you reach them?

The City of St. Louis Building Division issues building permits, conducts inspections and enforces the building code and zoning ordinances¹². Reach the Building Division at (314) 622-3313 or dps-building-division@stlouis-mo.gov¹². Its office is at 1200 Market Street, City Hall, Room 426, St. Louis, Missouri 63103-2826¹².

Direct parcel-use, district and setback questions to the Zoning Section at (314) 622-3666 or zoning@stlouis-mo.gov¹³. The Zoning Section is in Room 400 at 1200 Market Street, St. Louis, Missouri 63103¹³. It reviews commercial occupancy and building permits for zoning compliance; an application may be approved as a use by right, sent to a Conditional Use hearing or denied, with denials appealable to the Board of Adjustment¹³.

Does St. Louis city have zoning?

Yes. St. Louis city enforces zoning throughout the city, and a parcel's zoning district and any overlay determine its permitted uses and dimensional rules³. Current parcel zoning is available through the city's Address Search⁶. Setbacks depend on the district; side-yard rules can also vary with lot width and the proposed structure's type or height¹⁴. Residential garages and carports are typically no more than 5 feet from the alley or rear boundary¹⁴.

Minimum lot area is also district- and dwelling-specific rather than a single citywide number¹⁵. Districts A through E generally require at least 2,000 square feet for a detached single-family dwelling, with exceptions for qualifying existing lots¹⁵. Townhouse and two-family units need 1,000 square feet each in District C and 850 square feet each in District D¹⁶¹⁷. The available city rules do not confirm one minimum dwelling floor area for ordinary homes, so ask Zoning about the proposed design rather than treating minimum lot area as a minimum house size¹³.

How does sewer and septic work in St. Louis city?

St. Louis city is ordinarily served by public sanitary sewer through the Metropolitan St. Louis Sewer District, so onsite septic is not the usual arrangement⁷. Call MSD at (866) 281-5737 to establish new sewer service or service after a move¹⁸. For a sewer emergency, call (314) 768-6260¹⁸.

If a parcel lacks sewer access, do not begin septic work until the permitting authority is identified. Missouri requires a construction permit before installing or repairing most onsite wastewater systems, although some single-family residential lots may qualify for an exemption¹⁹. Permitting may be handled by the state program, a local contract authority or a local authority operating under its own ordinance²⁰. Missouri's septic rules also say a local ordinance may be more restrictive than the state standard, and the state page does not name St. Louis city specifically²¹. We could not confirm which agency administers onsite systems specifically within St. Louis city because the state lookup identifies St. Louis County agencies under the city entry. Ask the Building Division and Missouri Department of Health and Senior Services to resolve jurisdiction before designing or buying around an onsite system¹²¹⁹.

Can you live in an RV or tiny home on your land in St. Louis city?

We could not confirm a St. Louis city rule that allows long-term RV residence or temporary camping on private property, so get a parcel-specific answer from the Zoning Section before relying on an RV for housing¹³. A tiny house built on wheels cannot be used as a dwelling in St. Louis city: the city's Residential Code treats it like an RV meant for occasional recreational use, with one exception, a manufactured tiny house on a permanent chassis with an affixed HUD or FHA certification tag, which may be placed in a designated house-trailer park²². A tiny house meant as a dwelling unit must sit on an approved foundation and still goes through building and zoning review²²¹¹³.

An accessory dwelling unit is a clearer path for a small second home. St. Louis permits one attached or detached ADU per parcel in all residential zoning districts, subject to building permits and zoning review¹⁰. An ADU may be no taller than 25 feet and no larger than 1,200 square feet; it must sit at least 3 feet from side lot lines, and a detached ADU must be at least 10 feet from the primary structure¹⁰. Residential units must be inspected before occupancy⁵.

What are the steps to build or buy in St. Louis city?

Check the parcel's district and overlays through Address Search, then confirm uses, setbacks and lot-area rules with the Zoning Section⁶¹⁴.
Confirm sewer service with MSD and ask the city who has authority if an onsite wastewater system is proposed⁷¹⁹.
Prepare the project address, owner authorization when applicable, plans and the $25 building-permit application fee⁴.
Apply online or in person; an in-person submission requires 5 plan copies⁴.
Obtain any associated plumbing, electrical, mechanical, driveway or floodway permits that the work triggers⁴²³²⁴.
After all assigned city agencies approve the application, pay the permit fee and display the permit onsite during construction²⁵.
Complete Building Division inspections and obtain the required residential Certificate of Inspection before occupancy⁵²⁶.

What should you check before buying land in St. Louis city?

Start with the zoning district, overlays, legal use and lot dimensions; the same address can be affected by district-specific setbacks and minimum lot area⁶¹⁴¹⁵. Confirm public sewer service with MSD, and do not assume a private well or septic system is available simply because a listing mentions one⁷¹⁸. A Missouri water-well installation permit is generally required to construct or repair a private well, although a landowner may install the landowner's own well or pump under the cited state rules²⁷.

Check FEMA mapping before planning improvements because every construction project in a mapped city flood area needs a Floodway Development Permit even when the Building Code would not require a building permit²⁴. A new or modified driveway also requires a city driveway permit²³. For an existing residence, verify the Certificate of Inspection: residential sales and rentals require one before occupancy, and water and electricity must operate for the inspection⁹⁵.

Watch-outs

Building-permit fees are based on estimated construction cost, are non-refundable and are due after final approvals; the $25 application fee is due when filing²⁸.
Every residential unit must be inspected before occupancy, and an occupied dwelling without a current certificate carries a $200 residential inspection application fee instead of the standard $120 fee⁵.
A floodway permit can be required even when the proposed work does not otherwise require a building permit²⁴.
We could not confirm the St. Louis city-specific septic authority because the state lookup points to St. Louis County agencies; resolve jurisdiction before planning an onsite system¹⁹.
A tiny house on wheels used as a home is not allowed in St. Louis city, apart from a certified manufactured tiny house placed in a designated house-trailer park²².

Sources

Written October 10, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Compared with neighboring counties

Like 5 of its 6 neighbors, St. Louis City requires a building permit for a home.

Rule	St. Louis City	St. Louis County	St. Charles County	Jefferson County	Franklin County	Lincoln County	Ste. Genevieve County
Building permit	Required	Required	Required	Required	Required	Not required	Required
County zoning	Yes	Yes	Yes	Yes	Yes	No	Not published
Septic permits	MO Dept. of Health & Senior Services	County Dept. of Public Health	County Div. of Building & Code Enforcement	County Code Enforcement Div.	Franklin County	County Health Dept.	County Health Dept.

How St. Louis City scores

Seclusion16100% ev.

Self-Sufficiency1573% ev.

Admin Boringness4690% ev.

Durability52100% ev.

Property Autonomy47100% ev.

Carry Cost63100% ev.

Evidence strength: 92%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$187kTypical home

1%Property tax

$10,928Land / acre

41.8"Annual rain

3.2% of yrsSevere drought

13.2 / yr (+11.3)Mid-century 100°F days

16.6 daysMid-century dry spell

1.89" (+9%)Mid-century 1-day rain

1.84×Wildfire change factor

100%Forward climate coverage

$2,303Home insurance / yr

0.7% / yrInsurance growth

1.44%Nonrenewal rate

county median (2+ published ZIPs)Insurance basis

1,754,852People within 30 min

4,070,856People within 2 hr

1,291,158Radius comparison (15 mi)

4,563.8People / sq mi

0.3%Federal land

56.5°FAvg temp

Answers from the rulebook for St. Louis City

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

St. Louis City rules

Building permitRequired
New construction and structural changes in the City of St. Louis.
- A building permit is required for structural changes, major alterations, and new construction.
- Normal building maintenance may not require a permit in most instances.
- Separate plumbing, mechanical, and electrical permits may also be required.
- Historic-district and flood-area rules may impose additional approvals.
“A building permit is required when any structural change or major alteration is made to an existing building or when any new construction is undertaken.”
When a Residential Building Permit is Needed ↗Re-checked Oct 3, 2026
Building code adoptedAdopted (with conditions)
Construction projects inside the City of St. Louis.
- The permit page states that the purpose of the permit is to ensure compliance with all adopted City Building Codes.
“The purpose is to ensure that all adopted City Building Codes are adhered to in a project’s design and construction.”
Apply for a Building Permit ↗Re-checked Oct 3, 2026
Certificate of occupancyRequired
Residential and commercial properties requiring occupancy approval.
- Occupancy permits are required for residential and commercial properties.
- For residential sales, a Certificate of Inspection is required before occupancy is permitted.
- For rental units, a Certificate of Inspection is required before occupancy.
“Occupancy permits are required for residential and commercial properties to ensure that they comply with local building codes and are suitable for people to occupy.”
Building Division Permits Section ↗Re-checked Oct 3, 2026
Local zoningPresent
Zoning regulation within the City of St. Louis municipal jurisdiction, which is coterminous with the target county jurisdiction.
- The City Building Division enforces zoning ordinances; the claim is not a county-unincorporated zoning claim.
“The Building Division enforces the City building code, issues building permits, conducts building inspections, demolishes vacant buildings, and enforces zoning ordinances.”
Building Division ↗Re-checked Oct 3, 2026
Building in a floodplainRequired
All construction projects in areas designated as flood areas by FEMA Floodway or FIRM maps.
- A Floodway Development Permit must be issued even when a building permit may not be required by the Building Code.
- The rule applies to construction projects in a FEMA-designated flood area.
“For all construction projects in an area designed as a flood area per the FEMA Floodway or FIRM maps , a Floodway Development Permit must be issued even though a building permit may not be required by the Building Code.”
When a Residential Building Permit is Needed ↗Re-checked Oct 3, 2026
Permit processPublished (with conditions)
City building-permit application process.
- Applicants need the project address, $25 application fee, owner authorization if not the owner of record, and project plans.
- Applications may be submitted online or in person.
- Associated plumbing, electrical, or mechanical permits may be required.
- Assigned City agencies review the application; the permit is issued after approvals and payment of the permit fee.
- The permit document must be displayed onsite during construction.
“Once all assigned City agencies have approved your application, you will receive notification that your permit has been approved. At this time, you will be able to pay your permit fee and print the permit document, which needs to be displayed onsite during construction.”
Apply for a Building Permit ↗Re-checked Oct 3, 2026
County-wide zoningPresent
The Building Division's Zoning Section administers the Zoning Code in Title 26 with single-family, two-family, and commercial districts.
City of St. Louis Zoning Section ↗Scouted from the county site, not yet independently re-checked

Missouri rules that apply here

Zoning districtsPartial
Missouri statutory authority for counties to create zoning districts in unincorporated territory; this does not establish or publish the actual zoning districts for any particular county.
- The statute applies to unincorporated territory of counties subject to sections 64.211 to 64.295.
- Actual district boundaries, regulations, and maps depend on county adoption and are not supplied by this statewide statute.
- District regulations must be uniform for each class or kind of building or land use within each district, although regulations may differ between districts.
- The regulations must be made in accordance with a comprehensive plan.
“the unincorporated territory may be divided into districts of such number, shape and area as may be deemed best suited”
RSMo Section 64.261 — Zoning districts, creation, regulations ↗Re-checked Oct 5, 2026
Who permits septicMixed (with conditions)
Onsite wastewater treatment systems statewide in Missouri.
- DHSS administers minimum standards and permits through DHSS, local contract authorities, or local authorities operating under ordinance.
- County or city governments may adopt standards stricter than the state standard.
- DNR regulates lagoons serving anything other than single-family residences, systems discharging to surface waters, systems treating flows greater than 3,000 gallons per day and dispersing through soil absorption systems, and industrial wastewater systems.
- DNR approval is required for subdivisions, mobile home parks, and campgrounds when OWTS use is planned.
domestic wastewater flow threshold: <= 3000 gallons per day (DNR regulates systems with flows greater than 3,000 gallons per day when wastewater is dispersed through soil treatment or absorption systems)
“DHSS OWTS permitting falls under one of three authority types: DHSS Onsite Program, Local Authority (contract), or Local Authority via Ordinance. The application process varies by permitting authority.”
OWTS Construction Permit Process ↗Re-checked Oct 1, 2026
One more reviewed finding on this topic
- Mixed — Missouri wastewater treatment systems, including domestic onsite systems, larger-flow systems, direct discharges, lagoons, subdivisions, and industrial wastewater.
  “In Missouri, different state and local agencies are responsible for regulating wastewater treatment systems.”
  On-site Septic Systems and Subdivisions ↗Re-checked Sep 11, 2026
Septic permitRequired
Installing or repairing most onsite wastewater treatment systems in Missouri, including residential systems subject to state permitting.
- A construction permit is required before installing or repairing most OWTS.
- Some single-family residential lots may be exempt.
- For residential property less than three acres, a permit is required; the exemption does not apply in some counties, so the county authority must be checked.
- Work should not begin until a permit is issued or an exemption is confirmed.
- Effective August 28, 2026, application fees for onsite sewage disposal system construction, modifications, and repairs are temporarily suspended.
residential lot threshold: < 3 acres (The exemption does not apply in some counties.) · temporary permit-fee suspension effective date: 2026-08-28 (Applies to application fees associated with onsite sewage disposal system construction, modifications, and repairs.)
“A construction permit is required before installing or repairing most onsite wastewater treatment systems (OWTS). Some single family residential lots may be exempt from permitting.”
OWTS Construction Permit Process ↗Re-checked Sep 11, 2026
4 more reviewed findings on this topic
- Required — Installation or repair of most onsite wastewater treatment systems.
  “A construction permit is required before installing or repairing most onsite wastewater treatment systems (OWTS). Some single family residential lots may be exempt from permitting.”
  OWTS Construction Permit Process ↗Re-checked Oct 3, 2026
- Required — Construction or repair of Missouri onsite wastewater treatment systems where the state permitting rule applies.
  “Generally, a permit must be obtained before starting construction or repair work. However, certain residential properties may be exempt from state permitting requirements.”
  Onsite Wastewater Treatment ↗Re-checked Oct 3, 2026
- Required — Installing or repairing most onsite wastewater treatment systems statewide in Missouri.
  “A construction permit is required before installing or repairing most onsite wastewater treatment systems (OWTS). Some single family residential lots may be exempt from permitting.”
  OWTS Construction Permit Process ↗Re-checked Oct 1, 2026
- Required — Proposed campgrounds, mobile home parks, and subdivisions planning to use onsite wastewater treatment systems anywhere in Missouri.
  “DNR must approve subdivisions, mobile home parks and campgrounds if the use of OWTS is planned.”
  OWTS Construction Permit Process ↗Re-checked Oct 1, 2026
Septic inspectionLimited
Inspection or evaluation of existing onsite wastewater systems in connection with Missouri real-estate transfers.
- Local public health agencies generally no longer inspect existing systems for real-estate transfers.
- A private licensed inspector may perform an inspection or evaluation.
- A lender, buyer, or other transaction participant may require an assessment.
- Some local standards may be more stringent than state regulations.
- Inspections and evaluations are distinct; an inspection includes a hydraulic test, while an evaluation does not.
“For the most part, local public health agencies no longer inspect existing systems related to real estate transfer. The help of a licensed inspector can be obtained to check the condition of the system.”
Onsite Wastewater Treatment System Inspections Versus Evaluations ↗Re-checked Sep 11, 2026
One more reviewed finding on this topic
- Limited — Inspections of existing onsite sewage systems in connection with property sales statewide in Missouri.
  “Missouri Department of Health and Senior Services' (DHSS) rules governing onsite sewage systems cover minimum construction requirements, system inspections at the time of property sales, and requirements for percolation testers and soil evaluators.”
  health.mo.gov ↗Re-checked Oct 1, 2026
Off-grid sanitationLimited
Off-grid domestic wastewater treatment using onsite wastewater treatment systems where central sewer service is unavailable.
- Onsite systems treat and dispose of domestic sewage on the property where generated.
- A construction permit is generally required, including for residential property less than three acres, subject to county-specific exceptions.
- Wastewater may not be discharged into a road ditch or onto the ground.
- Local permitting authorities may impose additional requirements.
residential lot threshold: < 3 acres (The exemption does not apply in some counties.)
“Onsite wastewater treatment systems are sometimes referred to as "septic systems." These systems treat and dispose of domestic sewage on the property where it is generated.”
health.mo.gov ↗Re-checked Sep 11, 2026
One more reviewed finding on this topic
- Allowed (with conditions) — Use of onsite wastewater treatment systems as off-grid sanitation where central sewer service is unavailable in Missouri.
  “In Missouri, where central sewer service is not available, homeowners and small business owners use various types of onsite wastewater treatment systems (OWTS).”
  Onsite Wastewater Treatment ↗Re-checked Oct 1, 2026
Well permitLimited
Construction or alteration of a public well serving a Missouri public water system.
- Public water systems must receive written approval from the Missouri Department of Natural Resources Public Drinking Water Branch before constructing or altering a public well.
- The requirement does not apply when the system meets the charitable-and-benevolent-organization exemptions in section 640.116, RSMo.
- Anyone proposing to install a public well must contact the department’s regional office for a well-site survey.
- The survey addresses minimum isolation or setback distances from known or potential contaminant sources, including septic tanks, sanitary sewer lines, and landfills.
- Before applying for construction authorization, the public water system must obtain an estimated casing-depth letter from the Missouri Geological Survey Water Resources Center.
- There is no fee for the well-site-survey and estimated-casing-depth-letter services.
- Failure to obtain construction authorization may result in approval delays and possibly require the owner to properly plug the well and drill a new one according to 10 CSR 60-3.
public water system threshold: at least 15 service connections or regularly serves an average of at least 25 individuals daily, at least 60 days per calendar year
“Public water systems must receive written approval from the PDWB before constructing or altering a public well”
Who Regulates Water Wells in Missouri? - PUB4001 ↗Re-checked Oct 5, 2026
3 more reviewed findings on this topic
- Required — Construction or repair of water wells in Missouri, including St. Louis city if a private well is proposed.
  “A non-restricted water well installation permit is required to construct or repair a water well in Missouri.”
  Water Wells - PUB2945 ↗Re-checked Oct 3, 2026
- Required — A person or contractor conducting regulated work to drill, construct, repair, reconstruct, plug, or install pumps or pumping equipment in a water well, heat-pump well, monitoring well, or related well in Missouri.
  “A non-restricted permit is required to drill, construct, repair, reconstruct, plug, or install pumps or pumping equipment in a well.”
  Well and Pump Installation Contractor Permitting ↗Re-checked Oct 1, 2026
- Limited — Construction or repair of water wells, installation or replacement of pumps, and associated plumbing and electrical work in Missouri.
  “A non-restricted water well installation permit is required to construct or repair a water well in Missouri.”
  Water Wells - PUB2945 ↗Re-checked Oct 5, 2026
Agricultural exemptionAvailable (with conditions)
Farm buildings and farm structures used for agricultural purposes under the county building and land-use restriction provisions of RSMo sections 64.800 to 64.905.
- The exemption does not apply within incorporated portions of counties.
- The exemption applies to raising crops, livestock, orchards, or forestry and to specified rice-farming or flood-irrigation impoundments.
- For farm buildings or farm structures, the area must not be within the area shown on the flood hazard area map.
- The statute preserves the validity of county ordinances or orders adopted before March 4, 1991.
- Other laws and local requirements may still apply.
rice-farming or flood-irrigation berm height: <= 18 inches (small berms placed around a field to hold water for growing rice or flood irrigation)
“This section shall not apply to the erection, maintenance, repair, alteration or extension of farm buildings or farm structures used for such purposes in an area not within the area shown on the flood hazard area map.”
RSMo Section 64.890 — Building and land use restrictions; exemptions ↗Re-checked Oct 5, 2026
4 more reviewed findings on this topic
- Available (with conditions) — Erection, maintenance, repair, alteration, or extension of farm buildings or farm structures as against county fire-protection or fire-prevention ordinances.
  “Notwithstanding any provision of law to the contrary, no fire protection or fire prevention ordinance adopted by any county in this state shall be exercised so as to impose regulations or to require permits with respect to the erection, maintenance, repair, alteration, or extension of farm buildings or farm structures.”
  RSMo Section 64.003 — Farm buildings and farm structures ↗Re-checked Sep 11, 2026
- Available (with conditions) — Erection, maintenance, repair, alteration, or extension of farm buildings or farm structures used for agricultural purposes under RSMo section 64.890, outside incorporated portions of counties and outside areas shown on flood hazard area maps.
  “This section shall not apply to the erection, maintenance, repair, alteration or extension of farm buildings or farm structures used for such purposes [...]”
  RSMo Section 64.890 ↗Re-checked Oct 1, 2026
- Available (with conditions) — Farm buildings and farm structures statewide, with respect to county fire-protection and fire-prevention ordinances.
  “no fire protection or fire prevention ordinance adopted by any county in this state shall be exercised so as to impose regulations or to require permits [...]”
  revisor.mo.gov ↗Re-checked Oct 1, 2026
- Available — Erection, maintenance, repair, alteration, or extension of farm buildings or farm structures with respect to county fire-protection or fire-prevention ordinances.
  “Notwithstanding any provision of law to the contrary, no fire protection or fire prevention ordinance adopted by any county in this state shall be exercised so as to impose regulations or to require permits with respect to the erection, maintenance, repair, alteration, or extension of farm buildings or farm structures.”
  RSMo Section 64.003 — Farm buildings and farm structures ↗Re-checked Oct 5, 2026
Subdividing landLimited
Subdivision plats in the unincorporated areas of counties covered by RSMo section 64.070 after the county commission adopts subdivision regulations.
- The county commission must first adopt subdivision regulations.
- The plat must first be submitted to the planning commission.
- If the county planning commission does not report upon the plat within thirty days, it may then be deemed approved.
- If amended or rejected by the planning commission, the action may be overruled and the plat approved only by the county commission, with the reasons for overruling spread upon the county commission minutes.
- The recorder of deeds may not record the plat until receiving a certificate of authority from the county zoning enforcement officer.
- The statute also permits a county planning commission, upon written request of an incorporated area's legislative body where there is no municipal planning commission, to pass upon subdivision plats within that incorporated area; those plats are subject to county planning commission rules and approval procedures.
planning commission reporting period: 30 days (If no report is made, the plat may then be deemed approved.)
“After the county commission shall have adopted such subdivision regulations, no plat of a subdivision of land within the unincorporated area of such county [...]”
RSMo Section 64.070 ↗Re-checked Oct 1, 2026
2 more reviewed findings on this topic
- Regulated (with conditions) — Subdivisions in which onsite wastewater treatment systems are planned.
  “DNR must approve subdivisions, mobile home parks and campgrounds if the use of OWTS is planned.”
  OWTS Construction Permit Process ↗Re-checked Sep 26, 2026
- Limited — Subdivision regulations adopted by Missouri cities, towns, or villages under RSMo section 89.410.
  “The planning commission shall recommend and the council may by ordinance adopt regulations governing the subdivision of land within its jurisdiction.”
  RSMo Section 89.410 ↗Re-checked Oct 1, 2026
Driveway accessRequired
Construction or modification of driveways within MoDOT right-of-way statewide.
- A permit is required for construction of driveways and modifications to existing driveways on MoDOT right-of-way.
- An initial online request must be submitted for each planned listed activity.
- Engineered plans, traffic studies, hydraulic analysis, traffic-control plans, surety deposits, or performance bonds may be required depending on the work.
- The rule does not establish a permit requirement for driveways outside MoDOT right-of-way.
“We require you to obtain a permit to work on MoDOT's Right of Way for: Construction of driveways”
Permits | Missouri Department of Transportation ↗Re-checked Sep 11, 2026
Permit feesPublished (with conditions)
Missouri Department of Natural Resources air construction permits statewide.
- Fees apply to air construction permits, not to every Missouri building or land-use permit.
- Construction permit fees include a filing fee and an hourly processing fee.
- The filing fee depends on the type of construction permit.
- The listed fees are effective January 1, 2026.
- Fees applicable until December 31, 2025 are available on the Air Construction Permit Fees white sheet.
- A convenience fee is charged for electronic payment.
portable source relocation filing fee: 300 USD · minor permit filing fee: 300 USD · minor permit processing fee: per 100 USD (hour) · general permit filing fee: 700 USD · new source review filing fee: 6000 USD (plus $100 per hour processing fee) · prevention of significant deterioration filing fee: 6000 USD (plus $100 per hour processing fee) · hazardous air pollutant filing fee: 6000 USD (plus $100 per hour processing fee) · temporary or pilot filing fee: 250 USD (plus $100 per hour processing fee)
“Construction permit fees include a filing fee and an hourly processing fee. The filing fee is dependent on the type of construction permit.”
Air Construction Permits ↗Re-checked Sep 11, 2026
One more reviewed finding on this topic
- Published (with conditions) — Missouri onsite wastewater treatment system construction, modification, and repair application fees administered under the statewide DHSS OWTS program.
  “Effective August 28, 2026, [...] the application fees associated with on-site sewage disposal system construction, modifications, and repairs will be temporarily suspended.”
  OWTS Construction Permit Process ↗Re-checked Oct 5, 2026
county zoning authorityLimited
Missouri county zoning authority over unincorporated land.
- RSMo § 64.850 applies to counties of the first class without a charter and counties of the second, third, or fourth class.
- RSMo § 64.620 applies to counties of the second or third class to which §§ 64.510–64.690 apply.
- Adoption under §§ 64.510–64.690 requires approval by vote of the people under § 64.530.
- The authority applies in unincorporated portions and not incorporated portions.
- The regulations must be in accordance with a comprehensive plan.
- Under § 64.090, the zoning power does not apply to raising crops, livestock, orchards, or forestry; seasonal or temporary rice-farming or flood-irrigation impoundments; specified farm structures outside mapped flood-hazard areas; or underground mining entered through shafts outside mapped flood-hazard areas.
- Existing lawful uses and specified public-utility services are protected under the cited statutory schemes.
“the county commission of any county of the first class not having a charter form of government, or of any county of the second, third or fourth class may, after approval by vote of the people as provided in section 64.845, regulate and restrict, by order of record, in the unincorporated portions of the county, the height, number of stories, and size of buildings, the percentage of lots that may be occupied, the size of yards, courts and other open spaces, the density of population, the location and use of buildings, structures and land for trade, industry, residence or other purposes.”
RSMo § 64.850 — County commission may prescribe zoning regulations ↗Re-checked Oct 1, 2026
2 more reviewed findings on this topic
- General — Missouri counties adopting zoning regulations for unincorporated territory.
  “If a majority of the votes cast is in favor of county zoning, the county commission shall proceed with a program of county zoning”
  RSMo § 64.090 — Planning and zoning powers of county commission ↗Re-checked Sep 21, 2026
- Limited — Missouri county zoning of unincorporated land.
  “counties of the second, third or fourth class may, after approval by vote of the people [...] in the unincorporated portions of the county”
  RSMo § 64.090 — Planning and zoning powers of county commission ↗Re-checked Oct 1, 2026
county building authorityLimited
County authority to regulate residential construction and issue building permits in unincorporated areas of Missouri.
- The authority under sections 64.170 to 64.200 applies to counties of the first and second classification.
- A county that had not adopted a building code before August 28, 2001, must obtain voter approval before adopting one under those sections.
- Only voters in the area affected by the proposed code may vote; incorporated-territory citizens cannot vote on a code affecting a county.
- The county commission must hold at least three public hearings and provide the statutory newspaper publication and county posting notices before adoption.
- Regulations adopted under section 64.180 apply to unincorporated territory, except as otherwise provided.
- Adopted or amended codes after August 28, 2001, must use a current, calendar year 1999 or later edition of a nationally recognized building code, as amended.
- A county building ordinance may not conflict with liquefied petroleum gas installations governed by section 323.020.
public hearings before adoption: >= 3 hearings minimum (Section 64.180(3)) · newspaper notice: >= 15 days (Notice of hearing time and place must be published in at least two newspapers having general circulation within the county) · posted notice: >= 15 days (Notice must be posted in four conspicuous places in the county) · minimum nationally recognized building-code edition: >= calendar year 1999 edition year (Applies after August 28, 2001, under section 64.180)
“The regulations adopted shall be applicable to the unincorporated territory of the county, except as otherwise provided herein”
RSMo Section 64.170 — County commissions control construction; issue building permits ↗Re-checked Oct 1, 2026
2 more reviewed findings on this topic
- Limited — County regulation of construction and issuance of building permits for buildings, including residential construction, in Missouri counties, with the practical focus on county-controlled areas outside incorporated territory.
  “the county commission in all counties of the first and second classification [...] is for this purpose empowered [...] to adopt [...] regulations to control the construction”
  RSMo § 64.170 — County commissions control construction and issue building permits ↗Re-checked Sep 21, 2026
- Limited — Missouri counties' authority to require permits and regulate residential construction in unincorporated areas.
  “Before the adoption of such code of regulations, the county commission shall hold at least three public hearings thereon”
  RSMo § 64.170 — County commissions control construction; issue building permits ↗Re-checked Oct 1, 2026

Inside cities and towns in St. Louis City

Municipal rules found while researching the county. They apply inside that city or town, not to unincorporated land.

Building permitRequired
Structural changes, major alterations, and new construction in St. Louis City.
- Normal building maintenance usually does not require a permit.
- Separate plumbing, mechanical, and electrical permits are required when applicable.
- Floodway development permits are required in mapped flood areas even when a building permit is not required.
accessory building threshold: > 50 square feet · application fee: 25 USD (per application)
“A building permit is required when any structural change or major alteration is made to an existing building or when any new construction is undertaken.”
When a Residential Building Permit is Needed ↗Re-checked Oct 3, 2026
Owner-builder exemptionConditional
A homeowner performing electrical work in the City of St. Louis.
- The homeowner must pass a short Building Division Electrical Section test demonstrating sufficient knowledge of the Electrical Code.
- The property must be an owner-occupied, single-family dwelling.
- The work must be a room addition, repair, or modification to an existing electrical system.
- The homeowner may not apply for permits for service changes, rehabilitation, or new construction; those must be performed by a licensed contractor.
- The City page identifies the applicable electrical code as the 2017 National Electrical Code, adopted by Ordinance 70802 on August 1, 2018.
- The page directs applicants to contact the Building Division Electrical Section at 314-622-3313 or visit Room 425 in City Hall for testing and application information.
homeowner knowledge test: short test (Must determine sufficient knowledge of the Electrical Code to do the work.) · property type: owner-occupied, single-family dwelling · permitted work: room addition, repair, or modification to an existing system · prohibited work: service changes, rehab, or new construction (Must be performed by a licensed contractor.)
“As a homeowner, you can receive an electrical permit under the following conditions: You pass a short test given by the Building Division Electrical Section to determine that you have sufficient knowledge of the Electrical Code to do the work. You are performing work on an owner-occupied, single-family dwelling. You are performing a room addition, repair, or modification to an existing system. You may not apply for permits for service changes, rehab, or new construction. Those need to be performed by a licensed contractor.”
Apply for an Electrical Permit ↗Re-checked Oct 1, 2026
Building code adoptedAdopted
City building, residential, energy, fire, plumbing, mechanical, fuel-gas, electrical, existing-building, and property-maintenance codes.
- The page lists multiple adopted editions and ordinance numbers, including 2018 codes and the 2021 Uniform Plumbing Code.
- The City zoning ordinance is separately listed as Ordinance 59979.
“2018 International Building Code Ordinance 70794 Date adopted: 08-01-18”
Building Codes Adopted by the City ↗Re-checked Oct 3, 2026
InspectionsRequired
City building inspections and residential Housing Conservation District inspections.
- The Building Division conducts building inspections.
- 100% of property in St. Louis is located in a Housing Conservation District.
- Ordinance 71835 requires a City Housing Conservation District Inspection of any property located in the district.
- Residential units must be inspected before occupancy.
- Rental dwelling units require reinspection every three years or upon a change in occupancy; owner-occupied properties are exempt from that reinspection.
- The residential application fee is $120, or $200 if a resident is found occupying a dwelling without a current certificate; additional same-address applications are $65 per unit.
- Water and electric must be operable at inspection.
- Violations generally must be repaired within 30 days, subject to possible extensions for weather or other specific causes.
residential inspection application fee: 120 USD ($200 if occupied without a current certificate) · additional same-address application: 65 USD (per unit) · certificate validity: 12 months (valid certificates do not require reinspection during that period) · rental reinspection interval: 3 years (or upon a change in occupancy)
“Units must be inspected before they are occupied.”
Building Division ↗Re-checked Oct 3, 2026
Certificate of occupancyRequired
Residential sales, rental units, and occupancy of vacant residential units in St. Louis City.
- For residential sales, a Certificate of Inspection is required before occupancy.
- For rental units, a Certificate of Inspection is required before occupancy.
- A certificate is required before occupying a vacant residential unit.
- A certificate is required before sale of an occupied structure if none was issued within the prior 12 months.
certificate validity: 12 months (valid certificates do not require reinspection)
“For residential sales, a Certificate of Inspection must be obtained before occupancy of the unit is permitted. For rental units, a Certificate of Inspection must be obtained before occupancy of the unit.”
Apply for a Residential Occupancy Permit (Housing Conservation Inspection) ↗Re-checked Oct 3, 2026
One more reviewed finding on this topic
- Required — Residential sales and rental-unit occupancy in St. Louis City.
  “For residential sales, a Certificate of Inspection must be obtained before occupancy of the unit is permitted.”
  Apply for a Residential Occupancy Permit (Housing Conservation Inspection) ↗Re-checked Oct 3, 2026
Local zoningPresent (with conditions)
City of St. Louis zoning regulation, including parcels within the county-equivalent city.
- Zoning Section administers and enforces the City zoning code.
- Form-Based Districts and other overlay regulations may override underlying zoning.
“Current zoning for all parcels is available on Address Search.”
Answers to Common Zoning Questions ↗Re-checked Oct 3, 2026
One more reviewed finding on this topic
- Present (with conditions) — Land-use zoning throughout the City of St. Louis.
  “The Building Division enforces the City building code, issues building permits, conducts building inspections, demolishes vacant buildings, and enforces zoning ordinances.”
  Building Division ↗Re-checked Sep 26, 2026
Zoning districtsPublished
City zoning districts and zoning-map administration.
- The City Zoning Section provides a zoning district map and administers the City Zoning Code in Title 26.
- Specific district dimensional standards were not extracted here.
“Zoning District Map [...] The Zoning Section reviews all commercial occupancy and building permits for compliance with the Zoning Code which is located in Title 26 of the 1994 City of St. Louis Revised Code.”
Zoning Section ↗Re-checked Oct 3, 2026
Minimum lot sizeDistrict specific (with conditions)
Residential and related dwelling uses subject to the City of St. Louis Zoning Code density-of-population provisions in districts A through E; requirements vary by zoning district and dwelling type.
- District A: generally 2,000 square feet of lot area for each dwelling unit under Ordinance 72027, except qualifying lots of record may be used for one single-family dwelling if yard regulations are met.
- District B: 2,000 square feet for single-family dwellings; other dwellings generally require 1,250 square feet for each dwelling unit, with conversion townhouses exempt from minimum lot area.
- District C: 2,000 square feet for detached single-family dwellings; 1,000 square feet for each townhouse or two-family dwelling unit; 1,500 square feet for each multiple-family dwelling unit; conversion townhouses are exempt from minimum lot area.
- District D: 2,000 square feet for detached single-family dwellings; 850 square feet for each townhouse or two-family dwelling unit; 750 square feet for each multiple-family dwelling unit, or the lawful pre-rehabilitation amount.
- District E: 2,000 square feet for detached single-family dwellings; 750 square feet for each townhouse or two-family dwelling unit; 250 square feet for each multiple-family dwelling unit; conversion townhouses are exempt from minimum lot area.
- Ordinance 72027 states that it becomes effective immediately upon passage and approval; the City ordinance page gives an effective date of 07/11/2025.
- The ordinance contains exceptions for qualifying pre-existing lots and cross-references additional yard and use regulations.
District A single-family lot area: >= 2000 square feet per dwelling unit (Qualifying lots of record may be used for one single-family dwelling if yard regulations are met.) · District B single-family lot area: >= 2000 square feet (Lots of record prior to the effective date of Ordinance 45309 may be used for one single-family dwelling if yard regulations are met.) · District B other dwelling lot area: >= 1250 square feet per dwelling unit (Except as provided in Section 26.24.020.3(C); conversion townhouses are not required to have minimum lot area.) · District C townhouse or two-family lot area: >= 1000 square feet per dwelling unit (Conversion townhouses are not required to have minimum lot area.) · District C multiple-family lot area: >= 1500 square feet per dwelling unit (Existing lawful amount before rehabilitation may apply.) · District D townhouse or two-family lot area: >= 850 square feet per dwelling unit (Conversion townhouses are not required to have minimum lot area.) · District D multiple-family lot area: >= 750 square feet per dwelling unit (Existing lawful amount before rehabilitation may apply.) · District E townhouse or two-family lot area: >= 750 square feet per dwelling unit (Conversion townhouses are not required to have minimum lot area.) · District E multiple-family lot area: >= 250 square feet per dwelling unit
“The bill reduces minimum lot size requirements for single-family dwellings from 4,000 square feet per unit in districts “A” through “E” and reduces minimum lot size requirements for two-family dwellings from 2,500 square feet per unit to 1,250 square feet per unit in district “B”.”
Ordinance 72027 -- Amending the Zoning Code for Minimum Lot Size for Single-Family and Two-Family Dwellings ↗Re-checked Oct 4, 2026
4 more reviewed findings on this topic
- Specified — Single-family dwellings in City of St. Louis zoning Districts A through E, subject to the applicable chapter and exceptions.
  “Except as provided in Section 26.20.020.2(B), there shall be a lot area of not less than four thousand (4,000) two thousand (2,000) square feet for each dwelling unit.”
  Zoning Section ↗Re-checked Oct 7, 2026
- Specified — Single-family, two-family, and other dwellings in City of St. Louis zoning District B under Section 26.24.080.
  “Other dwellings, except as provided in Section 26.24.020.3(C)., shall have a lot area of not less than two thousand five hundred (2,500) one thousand, two hundred fifty (1,250) square feet for each dwelling unit.”
  Zoning Section ↗Re-checked Oct 7, 2026
- Specified — Detached single-family, townhouse, two-family, and multiple-family dwellings in City of St. Louis zoning District C under Section 26.28.090.
  “Town houses and two-family dwellings shall have a lot area of not less than 1,000 square feet for each dwelling unit therein.”
  Zoning Section ↗Re-checked Oct 7, 2026
- Specified — Detached single-family, townhouse, two-family, and multiple-family dwellings in City of St. Louis zoning District D under Section 26.32.090.
  “Multiple-family dwelling units shall have a lot area of not less than seven hundred fifty (750) square feet for each dwelling unit thereon, or as was lawfully provided in an existing building prior to rehabilitation.”
  Zoning Section ↗Re-checked Oct 7, 2026
SetbacksSpecified
Front, side, and rear setbacks under the applicable City zoning district.
- Setbacks depend on the parcel's zoning district.
- Side-yard setbacks may be modified based on lot width in zones A and B and the type or height of the proposed structure.
- Rear-yard requirements apply to primary structures; residential garages and carports are typically 5 feet or less from the alley or rear boundary.
garage/carport alley or rear boundary distance: <= 5 feet (the FAQ describes this as typical)
“Setbacks- front, side, and rear- depend on the zoning district. Once you verify the zoning designation of the parcel, you can look up the applicable setbacks in the zoning code.”
Answers to Common Zoning Questions ↗Re-checked Oct 3, 2026
Living in an RVProhibited
All other tiny houses constructed on wheels, which the City of St. Louis Residential Code treats as similar to RVs intended for occasional recreational use, when used as a dwelling unit or mobile home for living purposes.
- The prohibition applies to tiny houses constructed on wheels other than manufactured tiny houses on a permanent chassis with an affixed HUD or FHA certification tag.
- A manufactured tiny house meeting that certification condition may be located in a designated house-trailer park for mobile homes.
- Tiny houses intended to be used as dwelling units must be anchored to an approved foundation.
“Tiny houses intended to be used as a dwelling unit shall be anchored to an approved foundation. Manufactured tiny houses constructed on a permanent chassis with wheels by either the manufacturer or owner and which have an affixed HUD or FHA certification tag may be located in a designated house-trailer park for mobile homes. All other tiny houses constructed on wheels will be considered as similar to RVs intended for occasional recreational use and not allowed to be used as a dwelling unit or mobile home for living purposes.”
Chapter 25.11 - Residential Code, Section R329.2 ↗Re-checked Oct 7, 2026
Accessory dwellingsAllowed (with conditions)
Attached and detached ADUs in all residential zoning districts.
- Building Division permits are required.
- Zoning review is part of the permitting process.
- One ADU per parcel.
- Maximum height is 25 feet.
- Area may be up to 50% of the primary house or 750 square feet, whichever is greater, but no more than 1,200 square feet.
- ADUs may not be built in front of the primary structure and must be at least 3 feet from side lot lines.
- Detached ADUs must be at least 10 feet from the primary structure.
- No off-street parking is required unless required parking for the primary house is removed.
maximum height: <= 25 feet · maximum area: <= 1200 square feet · side setback: >= 3 feet · detached ADU separation: >= 10 feet
“All ADUs can be legally permitted in all residential zoning districts. The specific use regulations can be found in Chapter 26.20.021 of the Zoning Code.”
Accessory Dwelling Units 101 ↗Re-checked Oct 3, 2026
Driveway accessRequired
Construction of a new driveway or modification of an existing driveway in St. Louis City.
- The official City services page identifies a driveway permit application for constructing a new driveway or modifying an existing driveway; detailed standards were not located in the opened text.
“Apply for a permit to construct a new driveway or modify an existing driveway”
Permits, Inspections, and Certifications ↗Re-checked Oct 3, 2026
Building in a floodplainRequired
All construction projects in mapped flood areas in St. Louis City.
- The mapped area must be designated as a flood area under FEMA Floodway or FIRM maps.
- A Floodway Development Permit is required even if the Building Code does not require a building permit.
“For all construction projects in an area designed as a flood area per the FEMA Floodway or FIRM maps, a Floodway Development Permit must be issued even though a building permit may not be required by the Building Code.”
When a Residential Building Permit is Needed ↗Re-checked Oct 3, 2026
Permit feesPublished (with conditions)
City building-permit fees.
- All City building-permit fees are non-refundable.
- Only the application fee is payable when the application is filed.
- The permit fee is required after final approvals and when the permit is ready for issuance.
application fee: 25 USD (per application) · permit fee, estimated cost $0-$1,000: 19 USD (plus application fee) · permit fee, estimated cost $1,001-$2,000: 23 USD (plus application fee) · permit fee, estimated cost $2,001-$3,000: 30 USD (plus application fee) · permit fee, estimated cost over $3,000: per 10 USD (per thousand estimated construction cost or fraction thereof, plus application fee)
“A $25 application fee per application. [...] Fees are based on total estimated project cost and are calculated as follows: [...] Over $3,000.00 estimated construction cost or fraction thereof | $25.00 | $10.00 per thousand estimated construction cost or fraction thereof”
Apply for a Building Permit ↗Re-checked Oct 3, 2026
One more reviewed finding on this topic
- Published (with conditions) — City building and plumbing permit fees.
  “Fees are based on total estimated project cost and are calculated as follows:”
  Apply for a Building Permit ↗Re-checked Oct 3, 2026
Permit processPublished (with conditions)
City building permit applications for residential and commercial projects.
- Applications may be submitted online or in person.
- Minimum materials include the project address, $25 application fee, owner authorization if applicable, and project plans.
- Associated plumbing, electrical, or mechanical permits may be required.
- The permit must be displayed onsite during construction.
- Approval depends on assigned City-agency reviews.
in-person plan copies: 5 copies (in-person submissions)
“You can apply in person by bringing your drawings to the Permit office in City hall during business hours, or you can apply online via the button below.”
Apply for a Building Permit ↗Re-checked Oct 3, 2026

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

Minimum dwelling size — Minimum dwelling floor area for residential units in the City of St. Louis.
Lot coverage — Lot-coverage limits under City zoning.
Building height — Building-height limits under City zoning or building rules.
Camping on your land — Temporary camping on private property in St. Louis City.
Tiny homes — Occupancy of tiny homes as residential dwellings in the City of St. Louis.

3 more unanswered

Manufactured homes
Mandatory utility hookup
Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Living off-grid in St. Louis City, Missouri

Is St. Louis City a good place to live off-grid or homestead?

St. Louis City scores 26/100 on the Bolthole Index, a weak county profile. Its strengths: manageable long-term carry cost. Watch-outs: workable self-sufficiency basics (41.8″/yr rainfall) and little seclusion — roughly 1,754,852 people within a 30-minute drive.

Do you need a building permit in St. Louis City, Missouri?

St. Louis City generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Missouri Department of Health and Senior Services. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

How much does land cost in St. Louis City, Missouri?

Land in St. Louis City runs about $10,928 per acre, based on the latest county data.

What is the water situation in St. Louis City?

St. Louis City gets about 41.8" of rain a year, with severe drought in roughly 3.2% of years.

How remote is St. Louis City?

A representative private-land location has about 1,754,852 people within a 30-minute drive and 4,070,856 within two hours. The road-network catchments count population across county lines and clusters of smaller cities; straight-line radius values remain available as a comparison.

Building permits, zoning and land rules in St. Louis city, Missouri