Bolthole Index

Monroe County, Florida

Zoning, building permits and septic rules in Key West, Florida

Key West, Florida sets its own zoning inside city limits through Chapter 122 of its Land Development Regulations1. Building permits for construction in the city go through the City of Key West Building Department, not the Monroe County counter2. Septic permits come from the Florida Department of Health in Monroe County, and the city bars subsurface septic absorption on lots under 48,400 square feet34.

At a glance

Zoning
Yes, city zoning under Chapter 122 of the Land Development Regulations1
Building permits
Issued by the City of Key West Building Department; we could not confirm the city's full permit rules2
Septic
Florida Department of Health in Monroe County issues septic permits; city bars subsurface absorption on lots under 48,400 sq ft34
RV living
Only in a licensed trailer park5
Minimum lot, SF district
6,000 sq ft (8,000 sq ft in two named areas)6
Height, SF district
25 feet, plus 5 feet for nonhabitable space under a pitched roof7
Growth cap
New homes need an allocation under the Building Permit Allocation System8

Who to call

Building permits

City of Key West Building Department

Building permits inside Key West city limits, including online permits through the city's eTRAKiT portal

305-809-3956

bldg@cityofkeywest-fl.gov

1300 White Street, Key West, FL 33040

Online permits →

Zoning

City of Key West Planning Department

Zoning, land development regulations, zoning district questions and the Building Permit Allocation System

305-809-3746

planning-dept@cityofkeywest-fl.gov

1300 White Street, Key West, FL 33040

Planning & zoning

Building Permit Allocation System (BPAS), City of Key West Planning Department

Allocation of new residential dwelling units in Key West

305-809-3746

Septic permits

Florida Department of Health in Monroe County

Septic (OSTDS) permitting and inspection for Monroe County, including Key West

305-293-7500

dohmonroe@flhealth.gov

Contact details are copied from each office’s official page and were checked against it on October 16, 2026.

Off-grid gear

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

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Does Key West have zoning, and what does it mean for RVs, tiny homes, lot size and setbacks?

Yes. Key West zones land inside city limits through Chapter 122 of its Land Development Regulations, with separate residential districts such as SF (single-family) and HDR-11. The Planning Department publishes a zoning map and answers district questions8.

District rules decide the numbers. In the SF district, the minimum lot is 6,000 square feet, rising to 8,000 square feet in two named areas6. Maximum height is 25 feet, plus 5 feet for nonhabitable space under a pitched roof7. Maximum building coverage is 35 percent, and 30 percent in those same two areas9. In HDR-1, the minimum lot size is 1 acre10.

RV living in Key West is tightly limited: city code requires RVs and trailers occupied as living quarters to be parked in a licensed trailer park5. We could not confirm a rule for tiny homes; ask the Planning Department at 305-809-37468. Accessory dwelling units in the SF district are allowed only as deed-restricted affordable housing for permanent residents11.

Do you need a building permit in Key West, and who issues it?

Inside Key West city limits, the City of Key West Building Department handles building permits and takes applications online through the city's eTRAKiT portal2. Unincorporated Monroe County rules and the Monroe County Building Department in Marathon do not apply inside the city.

The Planning Department states that an addition requires building and site plans prepared by a registered architect or engineer and must be approved and permitted by the building department8. The Florida Building Code is adopted statewide, so it applies inside Key West too12. We could not confirm the city's owner-builder rules, permit fees or a minimum dwelling size; ask the Building Department at 305-809-39562.

Why does a new home in Key West need a Building Permit Allocation System award?

The Building Permit Allocation System (BPAS) is the city's primary tool for regulating new residential development13. A new dwelling unit is not only a zoning and building-permit question; it also draws on the city's limited growth allocation. Plan a pre-application meeting with the Planning Department's BPAS planner before you commit to a lot13.

The same allocation shows up in the accessory-unit rule: an SF-district accessory dwelling unit is subject to BPAS availability11.

How do septic permits work inside Key West?

Septic permits for Key West addresses come from the Florida Department of Health in Monroe County, not the city, because Monroe County is not one of the 16 counties where the Florida Department of Environmental Protection now handles permitting14. Florida law requires a permit for any onsite sewage treatment and disposal system15.

In practice, a Key West septic tank is unusual. Central sewer is almost universally available in Monroe County, and wherever sewer is available it must be connected16. City code also bars a permit for a private sewage plant using subsurface absorption on a lot under 48,400 square feet4, and the Florida Keys' septic systems that remain must be performance based treatment systems16. Contact the Department of Health at 305-293-7500 before assuming a septic system is an option16.

Can you live in an RV or tiny home on your land in Key West?

Key West city code requires RVs, trailers and similar vehicles occupied as living quarters to be parked in a regularly licensed trailer park5. Camping in a public place, including beaches within city limits, is banned17. That leaves no clear route to living in an RV on a private lot in the city.

We could not confirm any rule for tiny homes in Key West. Manufactured homes are barred from coastal high hazard areas and coastal A zones18. Ask the Planning Department at 305-809-3746 before buying a lot for either8.

Building a home in Key West: the steps, in order

  1. Find the lot's zoning district on the city zoning map and read its Chapter 122 dimensional rules18.
  2. Meet with a Planning Department planner, and ask about the Building Permit Allocation System for new dwelling units13.
  3. Confirm flood status: development in flood hazard areas needs floodplain review, and the floodplain administrator inspects it19.
  4. Hire an architect or engineer for building and site plans, then apply through the City of Key West Building Department82.
  5. Ask the Florida Department of Health in Monroe County about sewer connection or any septic question16.

What stays with Monroe County, and what to check before you buy in Key West?

Septic permits and inspections stay with the Florida Department of Health in Monroe County for every address in the county, city or not3. The county's building and zoning rules cover only unincorporated Monroe County; for land outside Key West, see the Monroe County page20.

Before buying, weigh the numbers: typical home value in Monroe County is $966,26121 and a typical home insurance premium is $7,871 a year22. Conventional drain fields rate poorly in Monroe County's soils, so septic is rarely the answer23.

Watch-outs

  • Key West's own rules for building permits, owner-builders, permit fees and tiny homes were not confirmed; call the City of Key West Building Department at 305-809-3956 or the Planning Department at 305-809-374628.
  • Search results for Key West permits often show Monroe County pages; inside city limits the city's own Building Department, not the county counter, handles building permits2.
  • Development in flood hazard areas needs floodplain review inside Key West, and manufactured homes are barred in coastal high hazard areas1918.

Sources

  1. Key West Code Sec. 122-238 Dimensional requirements (SF) (Key West), quoted and re-checked
  2. City of Key West Building Department (cityofkeywest-fl.gov)
  3. Septic Tanks, quoted and re-checked
  4. Key West Code Sec. 74-64 Private sewage treatment (Key West), quoted and re-checked
  5. Key West Code Sec. 108-681 Camping vehicles and equipment (Key West), quoted and re-checked
  6. Key West Code Sec. 122-238 Dimensional requirements (SF) (Key West), quoted and re-checked
  7. Key West Code Sec. 122-238 Dimensional requirements (SF) (Key West), quoted and re-checked
  8. City of Key West Planning Department (cityofkeywest-fl.gov)
  9. Key West Code Sec. 122-238 Dimensional requirements (SF) (Key West), quoted and re-checked
  10. Key West Code Sec. 122-335 Dimensional requirements (HDR-1) (Key West), quoted and re-checked
  11. Key West Code Sec. 86-9 Definition of terms (Key West), quoted and re-checked
  12. 61G20-1.001 Florida Building Code Adopted (Florida statewide rule), quoted and re-checked
  13. Building Permit Allocation System (BPAS), City of Key West Planning Department (cityofkeywest-fl.gov)
  14. Septic Tanks, quoted and re-checked
  15. OSTDS Application Information (Florida statewide rule), quoted and re-checked
  16. Florida Department of Health in Monroe County (monroe.floridahealth.gov)
  17. Key West Code Sec. 62-4 No camping (Key West), quoted and re-checked
  18. Key West Code Sec. 34-136 Manufactured homes (Key West), quoted and re-checked
  19. Key West Code Sec. 34-128 Inspections (floodplain) (Key West), quoted and re-checked
  20. Current Planning, quoted and re-checked
  21. Typical home value (Zillow): Bolthole Index county data
  22. Typical home insurance premium: Bolthole Index county data
  23. 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

Written October 16, 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.

Answers from the rulebook for Key West

Key West’s own rules

  • Local zoningPresent (with conditions)

    Land inside Key West city limits

    • Zoning is in Chapter 122 of the Land Development Regulations with separate residential districts such as SF and HDR-1.
    “The dimensional requirements in the single-family residential district (SF) are as follows:”
  • Zoning districtsPartial

    Zoning districts inside Key West city

    • Full district list and map not opened; SF, HDR-1 and Airport (A) districts confirmed.
    “The dimensional requirements in the high density residential college road district (HDR-1) are as follows:”
  • Minimum lot sizeSpecified

    Single-family residential district (SF) inside Key West city

    • 8,000 sq ft in the Venetian Subdivision south of Riviera Canal and the area bounded by Flagler Drive, Casa Marina Court, White Street and Reynolds Street.
    • Duplexes conditional, minimum 10,890 sq ft.

    minimum lot area: >= 6000 sq ft (8,000 sq ft in two named areas)

    “Single-family and two-family units: 6,000 square feet, except that in the following areas the minimum lot area shall be 8,000 square feet:”
    One more reviewed finding on this topic
  • SetbacksSpecified

    HDR-1 district inside Key West city

    front setback: >= 20 ft · side setback: >= 10 ft · rear setback: >= 10 ft · street side setback: >= 10 ft

    “Minimum setbacks: a. Front: 20 feet. b. Side: 10 feet. c. Rear: 10 feet. d. Street side: 10 feet.”
    One more reviewed finding on this topic
  • Lot coverageSpecified

    HDR-1 district inside Key West city

    maximum building coverage: <= 40 percent · maximum impervious surface ratio: <= 60 percent

    “Maximum lot coverage: a. Maximum building coverage: 40 percent. b. Maximum impervious surface ratio: 60 percent.”
    One more reviewed finding on this topic
  • Building heightSpecified

    HDR-1 district inside Key West city

    • May be increased by referendum.

    maximum height: <= 25 ft (unless otherwise increased by referendum)

    “Maximum height: 25 feet, unless otherwise increased by referendum.”
    One more reviewed finding on this topic
  • Living in an RVLimited

    RVs and trailers occupied as living quarters inside Key West city

    • Parking of RVs is also regulated by Sec. 108-680 and 108-681(a)-(b); in SF and medium density districts RVs must be in the rear yard or qualifying side yard.
    “All automobile trailers, recreational vehicles and the like occupied for living quarters in the city shall be parked in a regularly licensed trailer park.”
  • Camping on your landLimited

    Camping inside Key West city; the opened rule covers public places only

    • Defined to include beaches within city limits.
    • Private-land camping rules not found, other than RV living-quarters rule in Sec. 108-681(c).
    “No person shall camp in a public place in Key West.”
  • Manufactured homesLimited

    Manufactured homes in flood hazard areas inside Key West city

    • Installed on permanent reinforced foundations and elevated to base flood elevation plus one foot.
    • Must be installed by a licensed installer.
    • Zoning-district rules for manufactured homes not found.
    “Manufactured homes are prohibited in coastal high hazard areas and coastal A zones.”
  • Accessory dwellingsLimited

    Single-family (SF) district lots with a detached single-family dwelling inside Key West city

    • Deed-restricted affordable, permanent residents only, no transient rental, no separate condo sale.
    • Subject to BPAS availability at 0.78 ESFU.

    accessory unit size: 300 to 600 sq ft

    “one (1) accessory dwelling unit is allowed as of right, and performance criteria”
  • Septic permitLimited

    Private sewage treatment plants with subsurface absorption inside Key West city

    • City code bars permits on lots under 48,400 square feet.
    • State department of health recommendations must be followed.

    minimum lot area for subsurface absorption: >= 48400 sq ft

    “No permit shall be issued for any private sewage treatment plant employing subsurface soil absorption facilities where the area of the lot is less than 48,400 square feet.”
  • Off-grid sanitationLimited

    On-site sewage systems inside Key West city

    • Septic tanks and cesspools may not discharge to any natural outlet.
    • Subsurface absorption plants need a lot of at least 48,400 square feet.
    “No septic tank or cesspool shall be permitted to discharge to any natural outlet.”
  • Subdividing landLimited

    Subdivision proposals inside Key West city (floodplain review only from opened section)

    • Plats must show flood hazard areas and design flood elevations.
    “Subdivision proposals, including proposals for manufactured home parks and subdivisions, shall be reviewed to determine that:”
  • Building in a floodplainRequired

    Development in flood hazard areas inside Key West city

    • Floodplain administrator inspects development; elevation certificates required for lowest floor.
    • Manufactured homes elevated to base flood elevation plus one foot.
    “Development for which a floodplain development permit or approval is required shall be subject to inspection.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Key West or Monroe County directly.

  • Building permit — Building permits inside Key West city
  • Owner-builder exemption — Owner-builder permits inside Key West city
  • Building code adopted — Building code inside Key West city
  • Inspections — Building inspections inside Key West city
  • Minimum dwelling size — Minimum dwelling size inside Key West city
10 more unanswered
  • Tiny homes
  • Who permits septic
  • Septic inspection
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Driveway access
  • Short-term rentals
  • Permit fees
  • Permit process

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.

Unanswered questions are usually a sign that Key West publishes no rule on the point, not that none exists. Monroe County’s page lists the county offices to call.

← All of Monroe County: county rules, score and offices