Bolthole Index

Montgomery County, Maryland

Building permits, zoning and septic rules in Montgomery County, Maryland

38Index Score / 100
#20 of 24 in Maryland

Montgomery County, Maryland requires a building permit before construction of a detached home or qualifying townhouse, and the Department of Permitting Services (DPS) issues it1. County zoning applies broadly, but Brookeville, Poolesville, Laytonsville, Rockville, Barnesville, Gaithersburg and Washington Grove are exempt from the County Zoning Ordinance23. Septic permits and inspections come from DPS Well and Septic, which is separate from building permits4.

At a glance

Building permit
Required for new detached homes and townhouses up to 3 stories; DPS issues it15
Zoning
Countywide under Chapter 59, except in several self-governing towns (Rockville, Gaithersburg and others)23
Septic
DPS Well and Septic handles permits and required inspections; only about 14% of soils lack severe conventional drain-field limits467
Wells
County well permit required before any drilling, plus a state drilling permit8
Tiny home
Allowed only as an accessory dwelling unit on a lot with an existing single-family detached house9
Manufactured/mobile home
Residential occupancy is limited to designated mobile-home zoning districts10
Owner-builder
You can pull your own permit and build your personal residence yourself1112

Who to call

Building permits

Montgomery County Department of Permitting Services (DPS)

Building, electrical, mechanical, right-of-way, sediment-control and floodplain-district permits and inspections for Montgomery County; also administers new-home code review

240-777-0311

2425 Reedie Drive, 7th Floor, Wheaton, MD 20902

Online permits →

Septic permits

Montgomery County DPS Well and Septic

Well drilling permits and septic system permits, plan review and required inspections for Montgomery County

240-777-6306

Online permits →

Zoning

Montgomery County Planning Department (Maryland-National Capital Park and Planning Commission)

Zoning code interpretation, the Chapter 59 zoning ordinance and zoning-district lookups for Montgomery County land

301-495-4610

2425 Reedie Drive, 14th Floor, Wheaton, MD 20902

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

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Do you need a building permit in Montgomery County, Maryland?

Yes. Montgomery County requires a permit before you build a detached one- or two-family home or a townhouse up to three stories above grade with its own exterior entrance, and Right-of-Way and Sediment Control applications must accompany the building-permit application15. If you hold title to the land and will build your own personal residence yourself, county law lets you pull the permit as an owner-builder, though you give up New Home Warranty and Home Builder Guaranty Fund protection12. A structure used exclusively for agriculture on land assessed for agricultural use is exempt from the building permit itself, but it still needs any electric, well and septic permits13. Montgomery County has adopted the 2021 International Code Council package with local amendments for commercial construction; the adopted package also includes the 2021 NFPA fire and life-safety codes with Maryland amendments14.

Who is the Montgomery County building department, and how do you reach them?

The Montgomery County Department of Permitting Services (DPS) is the building department; reach the main office at 2425 Reedie Drive, 7th Floor, Wheaton, MD 20902, phone 240-777-031115. DPS coordinates the building, right-of-way, sediment-control and other permit reviews for a new home, with a four-week commitment for its code review before required WSSC and M-NCPPC approvals are complete16. Permit costs vary by application: a filing fee is generally due when you apply, the balance is generally due before issuance, and the county adjusts its operating-cost factor each July 117. Well and septic applications go through DPS Well and Septic separately; call 240-777-6306 to schedule an inspection18.

Does Montgomery County have zoning?

Yes, countywide, through the Montgomery County Zoning Ordinance (Chapter 59); look up the property's zoning district, then check that district's standards in Chapter 592. Brookeville, Poolesville, Laytonsville, Rockville, Barnesville, Gaithersburg and Washington Grove are exempt from the county ordinance, so parcels there need the municipality's rules3. Rural dimensions depend on the mapped zone: RDT regular lots cap coverage by roofed buildings and structures at 10%, while RE-1 lots cap it at 15%; both cited district standards cap principal-building height at 50 feet, with agricultural buildings exempt from the RDT height cap19202122. Setbacks follow the mapped zone too: in RE-1 the principal-building minimums are 50 feet front, 17 feet side and 35 feet rear, while R-60 lots need 25 feet front, 8 feet side and 20 feet rear, and accessory structures must sit behind the principal building's rear building line2324. A manufactured or mobile home for residential use is limited to designated mobile-home zoning districts, so it is not automatically allowed on an ordinary rural parcel10.

How do septic permits work in Montgomery County?

DPS Well and Septic is the approving authority for septic systems in Montgomery County, working alongside Maryland Department of the Environment requirements425. A septic permit is required to serve a new home or to upgrade an existing system for an addition, runs for 12 months with one 6-month extension available, and is usually issued within about two weeks of a complete application26. Once installation starts, the county requires a minimum of two inspections before it will approve the system6. Soils are the real constraint here: only about 14% of Montgomery County's soils lack severe limitations for a conventional drain field, so a site evaluation matters before you buy7. Where a non-conventional system is needed, the county describes an approved pretreatment or aerobic treatment unit, engineered by a qualified professional and monitored by DPS and MDE for at least two years after startup27.

Can you live in an RV or tiny home on your land in Montgomery County?

Montgomery County expressly describes a tiny home as one possible accessory dwelling unit, but that unit must share a lot with a single-family detached house; it is not permitted with a townhouse, condominium, duplex or mobile home9. Residential use of a manufactured or mobile home is limited to designated mobile-home zoning districts, so confirm the parcel's mapped district before treating one as a homesite option102. We could not confirm a complete countywide rule for using an RV as the sole residence on every vacant rural lot outside a campground or licensed park. Ask the Montgomery County Planning Department's zoning information counter about the exact parcel and proposed occupancy before buying28.

Building a home in Montgomery County: the steps, in order

  1. Confirm the property's zoning district and Chapter 59 standards before design begins2.
  2. Line up the well permit if the lot lacks public water and the septic permit if it lacks public sewer826.
  3. Apply for the building, Right-of-Way and Sediment Control permits together; DPS commits to a four-week code review, while WSSC and M-NCPPC approvals have separate timing516.
  4. Resolve any Floodplain District permit before construction; new residential building is prohibited in the mapped 100-year floodplain29.
  5. Post the construction sign within 3 days after permit issuance, have it verified before work begins, and request each residential inspection at least 24 hours before it is needed3031.
  6. Pass the required building and septic inspections; a new home cannot be occupied until DPS issues its Residential Use and Occupancy certificate after the final inspection632.

What to check before you buy land in Montgomery County

Water and waste: public water and sewer are generally available in higher-density areas and major transportation corridors, while lower-density suburban and rural areas usually rely on permitted private wells and septic systems33826. Soils: only about 14% of Montgomery County soils lack severe limits for a conventional drain field, so make septic feasibility and system design part of due diligence7. Flood risk: new residential construction is prohibited in the mapped 100-year floodplain, and development in the Floodplain District requires a county permit plus applicable state and federal approvals2934. Access: a driveway that connects to a Montgomery County road needs a county driveway permit, while a driveway on a state or municipal road needs a permit from that jurisdiction instead35. Single-family lots are generally limited to one driveway entrance per street, and a second may be considered case by case for frontage of 90 feet or more36. Work in a state right-of-way also requires coordination with the MDOT State Highway Administration district office37. Taxes: the effective property-tax rate is about 0.9%, and the median annual bill is about $5,3413839. Montgomery County averages about 2,147 people per square mile, and the nearest city of 100,000 or more is about 21 miles from the county center4041.

Watch-outs

  • If your parcel is in Brookeville, Poolesville, Laytonsville, Rockville, Barnesville, Gaithersburg or Washington Grove, the county's zoning ordinance does not apply — check that town's own zoning office instead of DPS or M-NCPPC3.
  • We could not confirm a published minimum dwelling floor-area requirement; ask the Planning Department to confirm the rule for the parcel's specific zoning district before designing a home28.
  • The agricultural building-permit exemption only holds if the land is agriculturally zoned and assessed for agricultural use; if it is assessed for anything else, a full building permit and other requirements (including forest conservation) can apply, and a county bill (Bill 7-26) took effect July 16, 2026, so confirm the current rule with DPS before building1315.

Sources

  1. Residential New Homes, Single Family and Townhouses Permit Process (2026 county census)
  2. Find my zoning page, quoted and re-checked
  3. montgomerycountymd.gov, quoted and re-checked
  4. Non-Conventional (Innovative and Alternative) Septic Systems (2026 county census)
  5. Residential New Homes, Single Family and Townhouses Permit Process, quoted and re-checked
  6. Septic Permit Process, quoted and re-checked
  7. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  8. Well Permit Process, quoted and re-checked
  9. Montgomery County Provides Information about New Rules for Accessory Dwelling Units, quoted and re-checked
  10. Zoning Code Directory, quoted and re-checked
  11. Affirmation of Property Owner Acting as Building Contractor (2026 county census)
  12. Affirmation of Property Owner Acting as Building Contractor, quoted and re-checked
  13. Office of Agriculture FAQ, quoted and re-checked
  14. Commercial Division Home Page, quoted and re-checked
  15. Montgomery County Department of Permitting Services (DPS) (montgomerycountymd.gov)
  16. Residential New Homes, Single Family and Townhouses Permit Process, quoted and re-checked
  17. DPS Regulations, quoted and re-checked
  18. Montgomery County DPS Well and Septic (montgomerycountymd.gov)
  19. S-2677 Hearing Examiner Report, quoted and re-checked
  20. Final Staff Report, Exhibit 106, quoted and re-checked
  21. S-2677 Hearing Examiner Report, quoted and re-checked
  22. Final Staff Report, Exhibit 106, quoted and re-checked
  23. Section 4.4.6. Residential Estate - 1 Zone (RE-1), quoted and re-checked
  24. Section 4.4.9. Residential - 60 Zone (R-60), quoted and re-checked
  25. Non-Conventional (Innovative and Alternative) Septic Systems, quoted and re-checked
  26. Septic Permit Process, quoted and re-checked
  27. Non-Conventional (Innovative and Alternative) Septic Systems, quoted and re-checked
  28. Montgomery County Planning Department (Maryland-National Capital Park and Planning Commission) (montgomeryplanning.org)
  29. Floodplain Regulations, Executive Regulation 24-06AM, quoted and re-checked
  30. New Home Building Inspections, quoted and re-checked
  31. Residential New Homes, Single Family and Townhouses Permit Process, quoted and re-checked
  32. Montgomery County Code, Chapter 8, Buildings, quoted and re-checked
  33. Public Water & Sewer Service, quoted and re-checked
  34. Floodplain Permitting in Maryland (Maryland statewide rule), quoted and re-checked
  35. DPS - Driveway Permit Process, quoted and re-checked
  36. Driveway Construction Permit Policy Guidelines, quoted and re-checked
  37. Access Management/Permits - MDOT SHA (Maryland statewide rule), quoted and re-checked
  38. Effective property tax rate: Bolthole Index county data
  39. Median property tax bill: Bolthole Index county data
  40. Population density: Bolthole Index county data
  41. Straight-line distance from the county center to the nearest city of 100,000+ people: Bolthole Index county data

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.

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Compared with neighboring counties

Like all 6 of its neighbors, Montgomery County requires a building permit for a home.

RuleMontgomery CountyHoward CountyFrederick CountyCarroll CountyPrince George's CountyBaltimore CityWashington County
Building permitRequiredRequiredRequiredRequiredRequiredRequiredRequired
County zoningYesYesYesYesYesYesYes
Septic permitsCounty Dept. of Permitting ServicesCounty Health Dept.County Health Dept.County Health Dept.County Health Dept.MD Dept. of the Env.County Health Dept.

County locator

Montgomery County in Maryland

38
County map
Montgomery County highlighted among the Maryland counties · colored by Index score

How Montgomery County scores

Seclusion11100% ev.
Self-Sufficiency68100% ev.
Admin Boringness42100% ev.
Durability86100% ev.
Property Autonomy43100% ev.
Carry Cost44100% ev.

Evidence strength: 100%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$627kTypical home
0.9%Property tax
$10,739Land / acre
44.6"Annual rain
1.6% of yrsSevere drought
4.6 / yr (+4.4)Mid-century 100°F days
13.1 daysMid-century dry spell
2.07" (+7.6%)Mid-century 1-day rain
1.48×Wildfire change factor
100%Forward climate coverage
$1,638Home insurance / yr
2.8% / yrInsurance growth
0.53%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
605,916People within 30 min
11,331,364People within 2 hr
1,467,189Radius comparison (15 mi)
2,146.5People / sq mi
2%Federal land
88.9%Land at 15% slope or less
13.6%Soils rated "not limited" for septic (strict USDA rating)
40,586 acWorkable land screen
79.7 tonsBiomass / forest ac
55.1°FAvg temp

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Cities and towns in Montgomery County

Inside a city or town, that city usually issues building permits and sets zoning; the county’s rules above cover unincorporated land. Septic, wells and floodplain rules usually stay with the county or state everywhere.

Not yet researched: Town of Barnesville · Town of Brookeville · Town of Chevy Chase · Village of Chevy Chase Section Five · Village of Chevy Chase Section Three · Town of Chevy Chase View · Town of Chevy Chase Village · Town of Garrett Park · Town of Glen Echo · Town of Kensington · Town of Laytonsville · Village of Martin's Additions · Village of North Chevy Chase · Town of Poolesville · Town of Somerset · Takoma Park · Town of Washington Grove

Answers from the rulebook for Montgomery County

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

Montgomery County rules

  • Building permitRequired

    Construction of detached one- or two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress in Montgomery County.

    • The permit must be obtained before construction.
    • Right-of-Way and Sediment Control permits must be applied for when applying for the building permit.
    • Electrical, mechanical, public right-of-way, well, septic, and fire protection permits may also be required to complete new-home construction.
    • New-home permits must be reviewed and approved by DPS, WSSC, and MNCPPC before issuance.
    • Projects in Montgomery County municipalities may require additional permits or permissions from the municipality.
    • Permit fees are governed by the applicable DPS fee schedule; new-home construction is also subject to development impact taxes for transportation and schools.

    maximum height: <= 3 stories above grade plane (Applies to the cited detached one- or two-family dwellings and townhouses with a separate means of egress.)

    “A permit is required prior to construction of detached one- or two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress.”
  • Owner-builder exemptionAvailable (with conditions)

    A property owner seeking a residential building permit for a new personal residence constructed directly by the owner on the owner's property.

    • The property owner must hold title to the Montgomery County property.
    • Construction must be performed directly by the owner on the owner's own land solely for the owner's personal residence.
    • The owner must not contract with another person or company to erect, construct, manage, oversee, or supervise the home without notifying DPS and having the builder's registration information added to the permit.
    • The owner must acknowledge that the home is not covered by the New Home Warranty and that the owner may not be protected by consumer-protection laws or the Maryland Home Builder Guaranty Fund.
    • The owner must provide the required certificate stating that the personal residence is not covered by the New Home Warranty with the building permit application and with any sale to a consumer within the five-year statutory warranty period.
    • The waiver request may be rejected if information is false or misleading.

    statutory warranty period: 5 years (Applies to any sale to a consumer during that period.)

    “County law does allow a property owner to obtain a building permit for construction to be performed directly by the property owner, solely on the property owner’s property, for a home that is to be occupied by the property owner as a personal residence.”
  • Building code adoptedAdopted (with conditions)

    Commercial building construction and related code compliance in Montgomery County.

    • Montgomery County's adoption includes local amendments.
    • The adopted package includes NFPA 1 Fire Code 2021 and NFPA 101 Life Safety Code 2021.
    • State of Maryland Fire Prevention Code amendments under COMAR 29.06.01 also apply.

    International Code Council code edition: 2021 (with local amendments) · NFPA 1 Fire Code edition: 2021 (with State of Maryland Fire Prevention Code amendments) · NFPA 101 Life Safety Code edition: 2021 (with State of Maryland Fire Prevention Code amendments)

    “Applicants: Montgomery County has adopted the 2021 International Code Council codes with local amendments, NFPA 1 Fire Code – 2021, NFPA 101 Life Safety Code – 2021, with State of Maryland Fire Prevention Code amendments (COMAR 29.06.01).”
  • InspectionsRequired

    New-home construction subject to Montgomery County DPS residential building inspections.

    • A public notification construction sign must be posted within 3 days of permit issuance and verified by inspection before construction begins.
    • The inspection sequence includes footings, foundation/parging or backfill, wall check, wall bracing, framing/close-in, insulation, final, and other applicable inspections.
    • WSSC plumbing/gas inspections and fire-protection inspections may be prerequisites.
    • The final inspection requires specified completion items, including exterior finishes, smoke detectors, final grading, and applicable certificates or test results.
    • DPS will not conduct specified close-in or final inspections without the required approved WSSC inspections.

    sign posting deadline: 3 days after permit issue (Sign posting must be verified by inspection before other inspections can be scheduled.)

    “Sign of Public Notification of Construction shall be posted within 3 days of permit issue. The sign posting shall be verified by inspection prior to the start of construction.”
    One more reviewed finding on this topic
  • Certificate of occupancyRequired

    New buildings and buildings enlarged, extended, or altered to change from one use group to another in Montgomery County; residential new homes receive a Residential Use and Occupancy certificate after final inspection.

    • A new building may not be used or occupied until the certificate of use and occupancy is issued.
    • For an alteration changing the use group, continued use during the work must be discontinued within 30 days after completion unless the certificate is secured.
    • A temporary certificate may be issued before all permitted work is complete if the portion can be occupied safely.
    • For existing buildings, the Director must issue a certificate upon written request if there are no pending violations or orders and the alleged use previously existed.
    • The certificate must specify the use group, fire grading, allowable live load, occupancy load, and any special stipulations or conditions of the building permit.

    certificate issuance after written application: 10 days (When the building or structure is entitled to a certificate.)

    “It is unlawful for any person to use or occupy a building hereafter erected in whole or in part until the certificate of use and occupancy is issued by the Director in satisfaction of this Chapter.”
    2 more reviewed findings on this topic
    • Required — Use and occupancy certificates for new buildings and additions subject to Montgomery County commercial building requirements.
      “For new buildings and additions, it is unlawful [...] to use or occupy a building [...] until the associated certificate of use and occupancy (U&O) is issued.”
    • Limited — Residential Use and Occupancy certificates for detached one- or two-family dwellings and townhouses processed through Montgomery County DPS.
      “You will receive your Residential Use and Occupancy certificate shortly after the final inspection is passed and recorded in the DPS permit tracking system.”
  • County-wide zoningPresent

    County zoning administered through the Montgomery County Zoning Ordinance, Chapter 59, and property-specific zoning information.

    • The official county page directs users to determine a property's zoning and then consult the Montgomery County Zoning Ordinance (Chapter 59).
    • Certain municipalities are exempt from laws in the County's Zoning Ordinance; those municipalities are addressed separately in the local_zoning claim.
    “Find the zoning for your property, described above. Open the Montgomery County Zoning Ordinance (Chapter 59)”
  • Local zoningVaries (with conditions)

    Aggregate local zoning across Montgomery County, including county-administered areas and incorporated municipalities; the county zoning ordinance does not apply uniformly to every municipality.

    • The official county FAQ states that Brookeville, Poolesville, Laytonsville, Rockville, Barnesville, Gaithersburg, and Washington Grove are exempt from laws in the County's Zoning Ordinance.
    • Municipal zoning rules may therefore apply in exempt municipalities; the applicable municipal ordinance must be checked for the property.
    “The following municipalities are exempt from laws in the County's Zoning Ordinance: Brookeville, Poolesville, Laytonsville, Rockville, Barnesville, Gaithersburg and Washington Grove.”
  • Minimum lot sizeSpecified

    Residential Multi-Unit High Density-10 (R-10) zone, standard and optional methods, by building type.

    • The standard-method table specifies minimum site area, minimum lot area, frontage, density, setbacks, and coverage.
    • The optional method requires 20,000 SF usable area and lists minimum lot areas of 1,000 SF, 800 SF, 800 SF, and 20,000 SF by building type.
    • The optional-method density specification incorporates Chapter 25A MPDU thresholds and percentage-based density increases.

    standard minimum lot area, detached house: >= 2000 sq ft · standard minimum lot area, side duplex: >= 1000 sq ft · standard minimum lot area, over duplex: >= 2000 sq ft · standard minimum lot area, triplex or townhouse: >= 800 sq ft · standard minimum lot area, apartment: >= 20000 sq ft · optional-method minimum usable area: >= 20000 sq ft

    “Lot area | 2,000 SF | 1,000 SF | 2,000 SF | 800 SF | 20,000 SF [...] Usable area | 20,000 SF”
    One more reviewed finding on this topic
    • Specified — Residential Multi-Unit Low Density-30 (R-30) zone, standard method, by building type.
      “Lot area | 3,000 SF | 1,500 SF | 3,000 SF | 1,000 SF | 12,000 SF”
  • SetbacksSpecified

    Principal residential buildings and accessory structures developed under the RE-1 standard method in Montgomery County

    • The standards apply to the RE-1 zone.
    • The side-street setback is 50 feet only when the abutting lot fronts on the side street and is in a Residential Detached zone; otherwise it is 20 feet.
    • Lot width at the front building line and setback requirements may be reduced under Section 4.4.3.
    • Accessory structures on a lot or parcel abutting a national historical park must be set back at least 200 feet unless exempted under Section 6.4.3.C.3.
    • Accessory structures must be located behind the rear building line of the principal building.

    front setback: 50 feet · side-street setback when abutting lot fronts on side street and is in Residential Detached zone: 50 feet · side-street setback otherwise: 20 feet · side setback: 17 feet · sum of side setbacks: 35 feet · rear setback: 35 feet · accessory front setback: 80 feet · accessory side-street setback when abutting lot fronts on side street and is in Residential Detached zone: 50 feet · accessory side-street setback otherwise: 20 feet · accessory side setback: 15 feet · accessory rear setback: 10 feet (12 feet on a corner lot where the abutting lot fronts on the side street and is in a Residential Detached zone)

    “Principal Building Setbacks (min) [...] Front setback | 50' [...] Side setback | 17' [...] Sum of side setbacks | 35' [...] Rear setback | 35' [...] Accessory Structure Setbacks (min) [...] Front setback | 80' [...] Side setback | 15' [...] Rear setback, if not otherwise addressed | 10'”
    One more reviewed finding on this topic
    • Specified — Principal residential buildings and accessory structures developed under the R-60 standard method in Montgomery County
      “Principal Building Setbacks (min) [...] Front setback | 25' [...] Side setback | 8' [...] Sum of side setbacks | 18' [...] Rear setback | 20' [...] Accessory Structure Setbacks (min) [...] Front setback | 60' [...] Side setback | 5' [...] Rear setback, if not otherwise addressed | 5'”
  • Lot coverageSpecified

    R-200, R-90, R-60, and R-40 lots under 25,000 square feet where the lot and proposed construction satisfy Section 4.4.1.B Residential Infill Compatibility

    • The lot must have been created by a plat recorded before January 1, 1978, or by a resubdivision plat creating fewer than 6 lots from a lot previously created by a plat recorded before January 1, 1978.
    • The lot must be less than 25,000 square feet.
    • The proposal must be a new detached house, demolition and reconstruction of more than 50% of an existing detached house's floor area, or an addition of more than 50% of the detached house's floor area.
    • Coverage includes any building, accessory building, and weatherproofed floor area above a porch.
    • Coverage excludes a bay window 10 feet wide or less and 3 feet deep or less, a chimney, a porch, and up to 240 square feet of a detached garage when the garage is less than 350 square feet of floor area and less than 20 feet in height.

    maximum coverage for lot area less than 6,000 square feet: 30% of lot area · maximum coverage for lot area 6,000 square feet or greater and less than 16,000 square feet: 30%, less 0.001% per square foot of lot area exceeding 6,000 square feet · maximum coverage for lot area 16,000 square feet or greater: 20% of lot area

    “The standards in Section 4.4.1 .B apply to the R-200, R-90, R-60, and R-40 zones where: [...] b. the lot is less than 25,000 square feet in area; [...] Lot area less than 6,000 SF: | 30% of lot area [...] Lot area equal to or greater than 6,000 SF but less than 16,000 SF: | 30%, less .001% per square foot of lot area exceeding 6,000 SF [...] Lot area equal to or greater than 16,000 SF: | 20% of the lot area”
    4 more reviewed findings on this topic
    • District specific (with conditions) — Lots in the Montgomery County RDT zone, as reflected in the official S-2677 report.
      “Regular lot: All roofed buildings and structures 10% 10%”
    • District specific (with conditions) — Lots in the Montgomery County RE-1 zone.
      “Coverage (max) All roofed buildings and structures 15% 15%”
    • Specified — Lots and detached-house development under the R-60 standard method
      “Coverage (max) [...] Lot | 35% [...] Development with a detached house building type may have to satisfy Section 4.4.1 .B, Residential Infill Compatibility. [...] The lot coverage maximum does not apply to Religious Assembly.”
    • Specified — Lots and detached-house development under the RE-1 standard method
      “Coverage (max) | Lot | 15% [...] 2. Placement”
  • Building heightDistrict specific (with conditions)

    Buildings in the Montgomery County RDT zone, as reflected in the official S-2677 report.

    • The report notes that antenna towers are not buildings for purposes of the cited standards; the site's storage shed is the building considered.

    maximum building height: 50 feet

    “Principal Building (max) Overall building height (agricultural buildings are exempt) 50' 50'”
    3 more reviewed findings on this topic
    • District specific (with conditions) — Buildings in the Montgomery County RE-1 zone.
      “Principal Building (max) Overall building height 50' 50'”
    • Specified — Principal and accessory buildings developed under the R-60 standard method
      “Principal building - measured to highest point of roof surface, regardless of roof type; or | 35' - measured to mean height between the eaves and ridge of a gable, hip, mansard, or gambrel roof | 30' Accessory structure | 20'”
    • Specified — Principal and accessory buildings developed under the RE-1 standard method
      “Height (max) [...] Principal building | 50' Accessory structure | 50'”
  • Tiny homesAllowed (with conditions)

    A tiny home used as an accessory dwelling unit on a qualifying Montgomery County property.

    • The county describes a tiny home as an example of an accessory dwelling unit, subject to specific legal requirements.
    • The ADU must be located on the same lot as a single-family detached house.
    • The ADU is not permitted in a townhouse, condominium, duplex, or mobile home.
    • The ADU must be licensed with DHCA unless located in specified municipalities exempt from county licensing; Takoma Park has separate licensing requirements.
    • Required building permits are issued by DPS.
    • The ADU may not be used as a short-term vacation rental.
    “An ADU is a housing unit located on the same lot as a single-family detached house – subject to specific legal requirements. An ADU is not permitted in a townhouse, condo, duplex or mobile home and may not be used as a short-term vacation rental.”
  • Manufactured homesLimited

    Manufactured/mobile-home residential occupancy in Montgomery County zoning districts designated for mobile homes.

    • The official zoning directory identifies RMH as Planned mobile home parks with a minimum tract area of 15 acres and a maximum of 7 dwelling units per acre of usable area.
    • The official zoning directory identifies RMH-200 as One-Family/mobile homes with a minimum tract area of 5 acres and a minimum net lot area of 20,000 square feet.
    • The directory page states that it is an archive and may contain out-of-date information; current applicability should be checked against the current Chapter 59 zoning code and zoning map.
    • An accessory dwelling unit is not permitted in a mobile home under the county ADU requirements.

    RMH minimum tract area: >= 15 acres (Planned mobile home parks.) · RMH maximum density: <= 7 dwelling units per usable acre (Planned mobile home parks.) · RMH-200 minimum tract area: >= 5 acres (One-family/mobile homes.) · RMH-200 minimum net lot area: >= 20000 square feet (One-family/mobile homes.)

    “RMH | Planned mobile home parks | minimum tract area: 15 acres, maximum of 7 dwelling units/acre (of usable area)”
  • Who permits septicMixed

    Countywide septic-system permitting and approval in Montgomery County.

    • Montgomery County DPS Well and Septic is the local approving authority.
    • Maryland Department of the Environment requirements also apply.
    “the Department of the Environment and the Approving Authority (DPS Well and Septic) shall consider all possible methods for correcting existing system failures”
  • Septic permitRequired

    Installing a septic system for a new home, or upgrading or replacing an existing septic system to accommodate a building addition, in Montgomery County.

    • Repairs or replacements of existing systems are directed to the separate Septic Repair Permit Process.
    • For building permit applications received on or after July 1, 2024, when a septic permit is required to upgrade or relocate existing-system components for a building permit, all work and permit conditions must be completed before building-permit approval and issuance; this applies to additions/alterations only, not new construction.
    • The permit is valid for 12 months and may receive a one-time six-month extension; after expiration, a new application and fee are required.
    • A non-refundable filing fee is required, and electronic plans must be uploaded within 5 business days or the application may be voided and fees forfeited.

    permit validity: 12 months (One-time 6-month extension may be granted.) · permit processing time: generally within two weeks (Complete application package and property eligibility required.)

    “A septic system permit is required to install a septic system to serve a new home, or to upgrade or replace an existing septic system to accommodate a building addition.”
  • Septic inspectionRequired

    New septic-system installations in Montgomery County after installation begins.

    • A minimum of two inspections is required.
    • Inspection requests may be scheduled through the inspector or the Well and Septic inspection line at 240-777-6306.
    • Final system approval requires all required inspections to be successfully performed and all permit conditions met.

    minimum inspections: >= 2 inspections

    “Once installation begins, a minimum of two inspections are required.”
  • Off-grid sanitationAllowed (with conditions)

    Private onsite wastewater sanitation, including conventional and approved non-conventional septic systems, where public sewer is unavailable or onsite systems are otherwise applicable.

    • When public sewer is unavailable, approved new technology or experimental onsite systems may be used when a conventional onsite design cannot correct the problem or is not the best correction method.
    • Non-conventional systems require DPS and MDE review before approval and permit issuance.
    • An approved pretreatment unit is required for non-conventional systems, usually an aerobic treatment unit.
    • A qualified professional must design the system and a qualified, county-approved contractor must install it.
    • BAT systems require a perpetual maintenance agreement, and all systems must be monitored by DPS Well and Septic and MDE for at least two years after construction and start of use.

    minimum post-construction monitoring: >= 2 years

    “When public sewer is not available, and a conventional on-site system design cannot alleviate the problem or does not provide the best method of correction, new technology or experimental systems may be used.”
  • Well permitRequired

    Drilling any well in Montgomery County, including potable, irrigation, agricultural, monitoring/testing, geothermal, and dewatering wells.

    • A State Drilling Permit is also required; the licensed well driller submits the state application to DPS for review and approval.
    • A county well permit is valid for 12 months and may be extended in six-month increments upon request by the well driller; no extension fee is required.
    • The driller must notify the County one business day before potable or geothermal drilling begins, and an inspection request is required before grouting.
    • For potable wells serving a new home or replacement potable wells, Certificate of Potability sampling is required before the applicable use-and-occupancy approval.

    permit validity: 12 months (Six-month extensions may be requested by the well driller.) · advance notice before drilling: >= 1 business day (Potable and geothermal wells.)

    “A Well Permit must be obtained prior to drilling a well for any purpose, including to provide potable drinking water; water for irrigation or agricultural purposes; monitoring and testing; geothermal systems; and dewatering.”
  • Mandatory utility hookupConditional

    Water and wastewater service for properties in Montgomery County; the applicable service depends on location and availability.

    • Public water and sewer service is generally available in higher-density development areas and major transportation corridors.
    • In lower-density suburban and rural areas where public service is usually unavailable, private onsite wells and septic systems provide water supply and wastewater disposal.
    • Public service eligibility depends on the property's service-area category.
    • Public providers include WSSC Water, the City of Rockville, and the Town of Poolesville.
    “Residents and businesses in Montgomery County use a combination of public water and sewer service and private, on-site service (wells and septic systems), depending on their location.”
  • Agricultural exemptionConditional

    Agricultural structures on land in Montgomery County that is agriculturally zoned and receiving an agricultural use assessment.

    • The exemption applies to the building-permit process for an agricultural structure.
    • Amenities such as electricity require additional County permits.
    • If land is assessed for anything other than agriculture, a County building permit is required and other requirements may apply, including forest conservation.
    • Agricultural buildings still require necessary electric, well, and septic permits.
    • The building and associated erosion and stormwater control measures must be constructed under Montgomery Soil Conservation District oversight.
    • Bill 7-26 was signed April 16, 2026 and became effective July 16, 2026.
    “A building or structure [...] used exclusively for agricultural purposes on land used exclusively for agriculture is exempt from needing a building permit.”
  • Subdividing landRegulated (with conditions)

    Subdivision and resubdivision of land within Montgomery County's Chapter 50 jurisdiction

    • Any subdivision must be included on a plat approved by the Board and recorded in the land records before transfer of any part of the subdivided land.
    • A building permit may be issued only for a building on a lot or parcel shown on a recorded plat or on a parcel exempt from recording requirements under Subsection 3.3.B.
    • The Board administers Chapter 50.
    • The Chapter contains exemptions, including exemptions to its requirements under Section 3.3; the specific exemption must be checked for the parcel and transaction.
    “Any subdivision of land must be included on a plat approved by the Board and recorded in the land records before transfer of any part of the subdivided land. [...] A building permit may only be issued for a building located on a lot or parcel shown on a plat recorded in the County Land Records or on a parcel exempt from recording requirements under Subsection 3.3 .B”
  • Driveway accessLimited

    Single-family driveway entrances and driveway access design governed by Montgomery County's Driveway Construction Permit Policy Guidelines.

    • The placement requirements apply unless restricted by the Certified Site Plan or Record Plat.
    • A second entrance may be considered case-by-case for lot frontage of 90 feet or more.
    • An exception for a circular driveway may be granted where the residence fronts an arterial or neighborhood principal street and the second entrance would eliminate the need to reverse onto or from the roadway.
    • Driveway aprons must be installed on the street with the assigned house mailing address, except for corner lots.
    • No through-lot access is allowed.
    • All driveway entrances are subject to a sight-distance evaluation based on AASHTO guidelines.
    • Commercial, mixed-use, high-rise, and other development entrances must comply with the Certified Site Plan approved by the Montgomery County Planning Board; additional entrances may be permitted case-by-case by DPS in consultation with the Department of Transportation.
    • A roadside tree protection plan is required with the right-of-way permit application if the critical root zone of a public-right-of-way tree will be impacted; circular driveway applications may be denied if they impact a roadside tree.
    • A site-specific Temporary Traffic Control Plan is required for an arterial or higher-classification roadway with an 80-foot or greater right-of-way, a Central Business District roadway in Wheaton, Bethesda, or Silver Spring, or sidewalk closure exceeding 15 days; DPS may also require one when deemed necessary.

    minimum distance from projected curb-face intersection: >= 35 feet (Single-family residence driveway placement requirement unless restricted by Certified Site Plan or Record Plat.) · minimum distance from curb return tangent or curvature point: >= 25 feet (Single-family residence driveway placement requirement unless restricted by Certified Site Plan or Record Plat.) · minimum distance from property-line fillet intersection: >= 20 feet (Single-family residence driveway placement requirement unless restricted by Certified Site Plan or Record Plat.) · utility-pole and other facility clearance: >= 3 feet (Driveway apron horizontal clearance.) · storm-drainage-inlet clearance: >= 3 feet (Driveway apron clearance.) · permitted entrances: 1 per street (A second entrance may be considered case-by-case for lot frontage of 90 feet or more; circular-driveway exception described in the policy.) · minimum separation between two driveway entrances: >= 40 feet at property line (Applies when two entrances are permitted.) · roadway right-of-way threshold for TTCP: >= 80 feet (TTCP requirement also applies in listed Central Business Districts or for sidewalk closure longer than 15 days.)

    “The number of permitted driveway entrances that may be constructed on a single-family lot is restricted to one per street, a second entrance maybe considered for lot frontage of ninety (90) feet or more on case-by-case basis.”
    One more reviewed finding on this topic
    • Required — New residential or commercial driveway aprons, temporary construction entrances, restoration or repair of existing driveway aprons, and proposed driveway entrances connecting to a Montgomery County roadway.
      “If the proposed driveway entrance will connect to a Montgomery County roadway, a permit is required. If the proposed location is a State or municipal roadway, you must obtain a permit from that jurisdiction.”
  • Building in a floodplainRequired

    Development in the Montgomery County Floodplain District, including construction, substantial improvements, fill, temporary development, and new or replacement infrastructure.

    • The Floodplain District includes areas subject to the 100-year flood and waterways with drainage areas of 30 acres or greater.
    • A Floodplain District Permit is required for all development in the Floodplain District, subject to Chapter 19 exemptions for specified activities.
    • The permit may be granted only after necessary Maryland Department of the Environment and other applicable State and federal permits are obtained.
    • All new residential development is prohibited in the 100-year floodplain.
    • Development must comply with Section 8-29(a), be outside Floodway Limits, and fully offset flood-height effects where applicable.
    • Approved structures generally must have the lowest floor at least one foot above the 100-year flood elevation; basements are prohibited.
    • Manufactured homes and buildings are not permitted in the Floodplain District.
    • A minimum 100-foot stream-valley setback applies, reduced to the floodplain limits where those limits are less than 100 feet from the banks.
    • The application must include site, ownership, contractor, engineered-plan, elevation, and other documentation; additional analysis must show no reasonable alternatives outside the floodplain, minimum necessary encroachment, flood resistance, and no increased upstream or downstream flooding or erosion.
    • The regulation states an effective date of February 27, 2007.

    drainage-area threshold: >= 30 acres · lowest-floor elevation: >= 1 foot above 100-year flood elevation · stream-valley setback: 100 feet (Use floodplain limits if less than 100 feet from stream banks)

    “A Floodplain District Permit is required for all development including, but not limited to, construction of and/or substantial improvements to buildings and structures”
  • Permit feesVariable (with conditions)

    Permit, license, certification, zoning, right-of-way, sediment-control, stormwater-management, well, and septic applications administered or collected by Montgomery County DPS.

    • The DPS Fee Estimator is only an estimate; DPS performs the final calculation.
    • Fees are determined under applicable County Council resolutions or County Executive regulations.
    • The Enterprise Fund Stabilization Factor is adjusted up or down on July 1 of each year.
    • Generally, a filing fee is due at application and any balance is due before permit issuance.
    • For Engineered Sediment Control permits, the balance is due one year after permit issuance or before final inspection, whichever comes first.
    • Fee waivers or reductions cannot be honored.
    • Permitting fees are based on the application date when a new fee regulation takes effect before approval or issuance.

    annual fee adjustment: July 1

    “EFSF is adjusted up or down on July 1 of each year to cover DPS labor and operating costs”
  • Permit processPublished (with conditions)

    Residential new-home permit applications for detached one- or two-family dwellings and townhouses not more than three stories above grade plane with a separate means of egress.

    • A building permit is required before construction.
    • Right-of-Way and Sediment Control permit applications are required at the time of building permit application.
    • Electrical, mechanical, public right-of-way, well, septic, and fire-protection permits may also be required.
    • The project must conform to zoning requirements.
    • DPS, WSSC, and M-NCPPC review must be completed before issuance.
    • County municipalities may require additional permits or permissions.
    • DPS states a four-week code-review commitment; WSSC and M-NCPPC review times are outside DPS control.
    • A fee schedule and development impact taxes apply.

    DPS code review commitment: 4 weeks (WSSC and M-NCPPC must complete their reviews before issuance)

    “DPS is committed to completing code review within 4 weeks.”

Maryland rules that apply here

  • Zoning districtsPartial

    Statewide generalized zoning information published by the Maryland Department of Planning for planning and regional analysis; it is not a substitute for the applicable county or municipal zoning ordinance.

    • Each local jurisdiction is responsible for its own zoning, except certain municipalities that do not exercise planning and zoning authority.
    • Maryland has hundreds of unique local zoning categories.
    • MDP groups generalized zoning into Rural, Residential, and Other, further divided into 11 generalized zoning categories.
    • The generalized categories do not establish the complete regulatory zoning districts or permitted uses for a specific parcel.
    “To aid regional and state-level planning purposes, MDP classified zoning districts under three main groups—Rural, Residential, and Other—which are further broken down into 11 distinct Generalized Zoning Categories.”
  • Accessory dwellingsLimited

    Accessory dwelling unit development statewide under Maryland Land Use Article Title 4, Subtitle 5.

    • The subtitle applies only to land with a single-family detached dwelling unit as the primary dwelling unit.
    • Each legislative body must adopt a local law authorizing accessory dwelling unit development on or before October 1, 2026.
    • A local law may establish accessory dwelling unit safety standards.
    • A local law may prohibit full or partial conversion of an accessory structure when the only vehicular access is from an alley.
    • Construction must meet public health, safety, and welfare standards, including relevant building codes and adequate public facilities provisions.
    • A local law must exclude the accessory dwelling unit from density calculations and residential-growth limits applicable to the lot, parcel, or tract.
    • A local law may not establish side- or rear-yard setback requirements exceeding existing accessory-structure setback requirements.
    • Additional off-street parking requirements may be established only under the statutory considerations, with a waiver process and a completed parking study.

    local authorization deadline: 2026-10-01 · primary dwelling type: single-family detached dwelling unit · side and rear setback ceiling: <= existing accessory structure setback requirements

    “each legislative body shall adopt a local law authorizing the development of accessory dwelling units in accordance with this section.”
  • county zoning authorityGeneral

    Maryland counties adopting and enforcing zoning and planning laws, including for unincorporated county territory within the county's jurisdiction.

    • The authority is exercised through local laws and remains subject to other public general law, public local law, and any applicable State-government regulatory authority.
    • The statute states that the State policy is that planning and zoning controls are implemented by local government.
    “A county may enact local laws relating to zoning and planning to protect and promote public safety, health, morals, and welfare, including: [...] It is the policy of the State that planning and zoning controls shall be implemented by local government.”
  • county building authorityLimited

    Maryland counties requiring building permits and adopting or enforcing building codes for residential construction in unincorporated areas.

    • Local Government Article § 13-901 applies to all counties except Anne Arundel County, Baltimore City, Baltimore County, Cecil County, Charles County, Howard County, Prince George’s County, Queen Anne’s County, and Worcester County.
    • Under § 13-901(c), covered county governing bodies may regulate building construction, adopt and enforce building codes, require building permits, impose permit and inspection fees, and inspect buildings and structures.
    • Section 13-902 applies only to Calvert, Caroline, Dorchester, Frederick, Harford, Kent, and Worcester Counties.
    • Under § 13-902(c), a building or housing code generally does not apply to a building on a farm or premises devoted solely to agricultural uses, except that it applies in Calvert County to dwellings on which construction began after July 1, 1979 and in Frederick County to residential buildings or buildings constructed for human habitation regardless of location or auxiliary use.
    • Kent County must adopt a building code and housing code; Calvert, Caroline, Dorchester, Frederick, Harford, and Worcester Counties may adopt them.
    • A building code adopted under § 13-902 must require a building permit before a building is built or improved and include standards for structural safety, fire prevention, lighting, ventilation, and proper access.
    • Later amendments to codes incorporated by reference are not effective in Caroline, Frederick, Harford, Kent, and Worcester Counties until incorporated into the county code.
    • Separate county-specific provisions apply to Cecil, Charles, Queen Anne’s, and St. Mary’s Counties, including the Charles County exemption for farm buildings and other outbuildings costing less than $2,500.
    • The Maryland Building Performance Standards apply statewide to each building or structure for which a building permit application is received by a local jurisdiction on or after August 1, 1995.

    building permit before building is built or improved: true (Required in a building code adopted under Local Government Article § 13-902.) · Charles County farm-building or outbuilding cost exemption: < 2500 USD (The Charles County building code does not apply to farm buildings or other outbuildings costing less than $2,500.) · Maryland Building Performance Standards application date: >= 1995-08-01 (Applies to building permit applications received on or after this date.)

    “This section applies to all counties except: [...] The governing body of a county may: (1) regulate the construction of buildings and signs; (2) adopt a building code; (3) provide for enforcement of the code; (4) require permits for the construction of buildings and signs; (5) impose permit and inspection fees; (6) provide for inspection of buildings and structures;”

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 size requirements under Montgomery County zoning and land-use rules.
  • Living in an RV — Use of an RV as a sole residence on a vacant rural lot outside a County-authorized campground or other licensed park.

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 Montgomery County, Maryland

Is Montgomery County a good place to live off-grid or homestead?

Montgomery County scores 38/100 on the Bolthole Index, a marginal county profile. Its strengths: a durable current and mid-century hazard profile and workable self-sufficiency basics (44.6″/yr rainfall). Watch-outs: about 605,916 people within a 30-minute drive.

Do you need a building permit in Montgomery County, Maryland?

Montgomery County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Montgomery County Department of Permitting Services (on behalf of Maryland Dept. of the Environment). Owner-builders may act as their own contractor to build their home. 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 Montgomery County, Maryland?

Land in Montgomery County runs about $10,739 per acre, based on the latest county data.

What is the water situation in Montgomery County?

Montgomery County gets about 44.6" of rain a year, with severe drought in roughly 1.6% of years.

How remote is Montgomery County?

A representative private-land location has about 605,916 people within a 30-minute drive and 11,331,364 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.

How Montgomery compares in Maryland

Compare side-by-side →See all 24 Maryland counties ranked →