Bolthole Index

St. Louis County, Missouri

Zoning, building permits and septic rules in Sunset Hills, Missouri

Sunset Hills, Missouri requires a building permit for any new home, addition, pool or garage, and the first step is a municipal zoning approval from the city1. The city zones its own land2, while St. Louis County reviews and issues the actual building permit1. We could not confirm who handles septic permits inside city limits; start with the St. Louis County Department of Public Health3.

At a glance

Building permit
Required for new homes, additions, pools and garages; city zoning approval first, then county review1
Zoning
Yes, the city adopts and administers its own zoning districts24
Minimum lot, R-1
1 acre (43,560 square feet) for new single-family homes5
Front setback, R-1
50 feet; rear 35 feet6
City zoning review time
Normally 2 weeks7
Septic permits
Not confirmed inside city limits; ask St. Louis County Department of Public Health3

Who to call

Zoning

City of Sunset Hills, Public Works (municipal zoning approval)

Municipal zoning approval, the first step of every building permit inside Sunset Hills, and the city occupancy permit

314-849-3400

3939 S Lindbergh Boulevard, Sunset Hills, MO 63127

Building permits

St. Louis County Department of Transportation and Public Works — Codes and Ordinances

County building permit review, after the city zoning approval letter

314-615-5184

41 South Central Avenue, 6th Floor Clayton, MO 63105

Septic permits

St. Louis County Department of Public Health

Onsite wastewater (septic) permitting in St. Louis County; confirm whether it applies to your Sunset Hills address

314-615-0600

[email protected]

6121 North Hanley Road, Berkeley, MO 63134

Contact details are copied from each office’s official page and were checked against it on October 24, 2026.

Off-grid gear

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

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Does Sunset Hills, MO have zoning, and what does it mean for lot size and setbacks?

Yes. Sunset Hills divides the city into its own zoning districts and regulates land use, building height and yard areas through its Unified Development Ordinance2. The districts include parks and open space, Non-urban (NU), six single-family districts (R-1 through R-6), and commercial, light industrial and professional office districts4.

Dimensions depend on the district. In the R-1 Single Family District, new single-family detached homes need lots of at least one acre, or 43,560 square feet5. R-1 setbacks are 50 feet in front, 15 feet on the interior side and 35 feet in the rear, with 50 feet on a street-side lot line6. Maximum building height in R-1 is 40 feet8, and primary-use coverage is capped at 15 percent9.

The NU Non-urban district is larger: 127,680 square feet per lot, with a 50-foot front setback, 15 feet on the side and 35 feet at the rear10. Planned-development districts have their own standards in the ordinance6.

Do you need a building permit in Sunset Hills, and who issues it?

Yes. A building permit is required whenever you build or change a structure inside Sunset Hills, including new homes, additions, pools and garages1. Two offices share the work. The City of Sunset Hills reviews zoning conformance and issues a zoning approval letter, and St. Louis County then reviews and issues the actual building permit11. St. Louis County will not accept plans without that city letter11.

The city adopts the St. Louis County codes, including the 2015 International Residential Code12. The city also issues its own occupancy permit for new homes or a change of occupancy, separate from the county's final13. We could not confirm an owner-builder exemption or the inspection stages inside the city; ask the city's Public Works office.

How do septic permits work in Sunset Hills?

We could not confirm which agency permits septic systems inside Sunset Hills city limits. In St. Louis County generally, onsite wastewater permits come from the county, and the state's own list names both the St. Louis County Plumbing Department and the St. Louis County Department of Public Health, with incorporated areas possibly handled differently3. Missouri requires a construction permit before installing or repairing most onsite systems, and some single-family lots may be exempt14.

Before buying a lot that is not on public sewer, call the St. Louis County Department of Public Health at 314-615-060015. Wells follow state rules: a water-well installation permit is required to construct or repair a well in Missouri, and landowners may install their own well or pump without a permit under the cited law16. We could not confirm any additional city well rule.

Building a home in Sunset Hills: the steps, in order

  1. Confirm your lot's zoning district on the city's zoning map, since lot size and setbacks depend on it4.
  2. Prepare two copies of your plans with a site plan showing property lines and the building footprint with every dimension needed to check setbacks7.
  3. Submit them to the City of Sunset Hills for municipal zoning approval and pay the fee at submission; approval normally takes 2 weeks7.
  4. Collect the approved plans, pay the zoning-approval deposit at pickup, and take the plans to St. Louis County and your fire district7.
  5. Apply for the building permit with St. Louis County Codes and Ordinances at 314-615-518417.
  6. Before occupancy, obtain the city occupancy permit, which releases the escrow deposit13.

What stays with St. Louis County, and what to check before you buy in Sunset Hills

The county's own zoning and building rules cover only unincorporated land, so they do not govern a lot inside Sunset Hills18. For land outside city limits, see the St. Louis County page.

Check whether the lot lies in a flood hazard area, since the county requires floodplain plan review for development there19. Septic and well questions go to the county and state offices above. For context, St. Louis County's effective property tax rate is 1.2 percent20 and the typical home value is about $293,45821. We could not confirm rules for RVs, tiny homes, accessory dwellings or a minimum home size inside the city; ask Sunset Hills Public Works at 314-849-340011.

Watch-outs

  • Sunset Hills lots are zoned individually, so R-1 standards do not apply to a lot in NU or another district4.
  • Start with the city: St. Louis County will not accept plans without a Sunset Hills zoning approval letter11.
  • The city deposit is refundable only when the job is cleaned up and landscaping is complete13.
  • Missouri has temporarily suspended application fees for septic construction and repairs from August 28, 2026 pending new standards22.

Sources

  1. Municipal Zoning Approval (Building Permits) (Sunset Hills), quoted and re-checked
  2. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  3. OWTS Construction Permit Process — St. Louis County authorities, quoted and re-checked
  4. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  5. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  6. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  7. Municipal Zoning Approval (Building Permits) (Sunset Hills), quoted and re-checked
  8. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  9. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  10. City of Sunset Hills Unified Development Ordinance (Sunset Hills), quoted and re-checked
  11. City of Sunset Hills, Public Works (municipal zoning approval) (sunset-hills.com)
  12. Building Code Details (Sunset Hills), quoted and re-checked
  13. Municipal Zoning Approval (Building Permits) (Sunset Hills), quoted and re-checked
  14. OWTS Construction Permit Process (Missouri statewide rule), quoted and re-checked
  15. St. Louis County Department of Public Health (stlouiscountymo.gov)
  16. Water Wells - PUB2945, quoted and re-checked
  17. St. Louis County Department of Transportation and Public Works — Codes and Ordinances (stlouiscountymo.gov)
  18. Single-Family Dwelling Design Checklist, quoted and re-checked
  19. Bill No. 82, 2022 — Section 1003.101 FP Flood Plain District Regulations, quoted and re-checked
  20. Effective property tax rate: Bolthole Index county data
  21. Typical home value (Zillow): Bolthole Index county data
  22. OWTS Construction Permit Process, quoted and re-checked

Written October 24, 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 Sunset Hills

Sunset Hills’s own rules

  • Building permitRequired

    Construction or structural changes, including new homes, additions, pools, and garages, inside Sunset Hills city limits.

    • The City zoning-approval application is the first step.
    • The City reviews zoning conformance before the applicant takes the approval letter to St. Louis County for actual building-permit review.
    • County review time depends on project complexity.
    “A Building Permit is required whenever you build or change a structure (i.e. new homes, additions, pools, garages, etc.) within the city. An application for a Municipal Zoning Approval (PDF) from the City of Sunset Hills is your first step to getting the actual permit from St. Louis County. The city reviews your request for zoning conformance then you take the zoning approval letter to St. Louis County for the actual Building Permit review.”
  • Building code adoptedAdopted (with conditions)

    Building work inside Sunset Hills city limits.

    • The City identifies applicable St. Louis County codes, including the 2015 IRC, IBC, UPC, IMC/IFC, IEBC, ISPSC, IPMC, and the 2014 NEC.
    • The City's page lists implementation dates for the cited County code chapters.

    International Residential Code edition: 2015 · International Residential Code implementation date: 07/01/20

    “Recent Building Code adoption is as follows:”
  • Certificate of occupancyLimited

    New homes and residential structures where occupancy is changed inside Sunset Hills city limits.

    • The City requirement stated on the permit page is for release of an escrow.
    • The City permit is separate from St. Louis County's final indicating that occupancy is allowed.
    • The deposit is refundable only when the job is cleaned up and vegetation and landscaping are completed.
    “For new homes or any change of Occupancy, an Occupancy Permit will be required”
  • Local zoningPresent (with conditions)

    Land inside Sunset Hills city limits.

    • Uses and development remain subject to the applicable zoning district and other City ordinance provisions.
    “In order to regulate and restrict the location of businesses, industries, residences and other land uses and the location of buildings designed for specified uses; to regulate and limit the height and bulk of buildings hereafter erected or altered; to regulate and limit the intensity of the use of lot areas, and to regulate and determine the area of yards, courts, and other spaces within and surrounding such buildings, the City is hereby divided into the following districts.”
  • Zoning districtsPublished (with conditions)

    Zoning districts inside Sunset Hills city limits.

    • The official zoning map and its notations are part of the Ordinance.
    • Planned-development districts are also listed in the UDO.
    “The City is hereby divided into the following districts. Furthermore, such districts classifications as were in effect at the time of adoption of this Ordinance are hereby afterwards to be classified as follows: 1) POS: Parks and open space 2) NU: Non-urban 3) R-1: Single family 4) R-2: Single family 5) R-3: Single family 6) R-4: Single family 7) R-5: Single family 8) R-6: Single family 9) LC: Local commercial 10) GC: General commercial 11) LI: Light industrial 12) PO: Professional office”
  • Permit processPublished (with conditions)

    Municipal zoning approval preceding building-permit review for work inside Sunset Hills city limits.

    • Submit two plan copies with site plans showing property lines and building footprint dimensions needed for setback compliance.
    • Pay the associated fee at submission and the municipal-zoning-approval deposit at pickup.
    • After City Public Works approval, take the plans to St. Louis County and the applicable Fire District.

    City zoning approval normal processing time: 2 weeks (St. Louis County review varies by project complexity.)

    “Zoning approvals from the city normally take 2 weeks, so you will need to place this into your schedule. St. Louis County's review time depends upon the complexity of the project and can vary from a few days to a few weeks. St. Louis County will not accept your plans without a zoning approval letter from the City of Sunset Hills. You need to start with your zoning approval part of the process with the city first.”

Rules another office applies inside Sunset Hills

Sunset Hills does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum lot sizeSpecified

    New single-family detached dwellings in the City's R-1 Single Family District.

    • The R-1 purpose provision applies to new single-family detached dwellings.
    • Other UDO requirements may also apply.

    minimum lot area: >= 43560 square feet

    “The purpose of the R-1 District is to protect and preserve areas of low-density, estate-type, residential development and to allow for the construction of new single family detached dwellings on lots of not less than one (1) acre in size.”
  • SetbacksSpecified

    Development in the City's NU Non-Urban District.

    • Planned-development district standards are separately specified in Appendix A.

    front setback: >= 50 feet · interior side setback: >= 15 feet · side setback adjacent to street: >= 15 feet · rear setback: >= 35 feet

    “POS n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a NU 127,680 150 50 15 15 35 15 n/a n/a 40 R-1 43,560 150 50 15 50 35 15 - - 40”
    One more reviewed finding on this topic
  • Lot coverageSpecified

    Primary use coverage in the City's NU Non-Urban District.

    • The table lists no impervious-surface or total-lot-coverage percentage for NU.
    • Planned-development district standards are separately specified in Appendix A.

    primary use coverage: <= 15 percent

    “POS n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a NU 127,680 150 50 15 15 35 15 n/a n/a 40 R-1 43,560 150 50 15 50 35 15 - - 40”
    One more reviewed finding on this topic
  • Building heightSpecified

    Development in the City's NU Non-Urban District.

    • Planned-development district standards are separately specified in Appendix A.

    maximum height: <= 40 feet

    “POS n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a NU 127,680 150 50 15 15 35 15 n/a n/a 40 R-1 43,560 150 50 15 50 35 15 - - 40”
    One more reviewed finding on this topic

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Sunset Hills or St. Louis County directly.

  • Owner-builder exemption — Owner-built residential work inside Sunset Hills city limits.
  • Inspections — Building construction inside Sunset Hills city limits.
  • Minimum dwelling size — Principal dwellings inside Sunset Hills city limits.
  • Living in an RV — Long-term RV occupancy on private land inside Sunset Hills city limits.
  • Camping on your land — Temporary recreational camping on private land inside Sunset Hills city limits.
14 more unanswered
  • Tiny homes
  • Manufactured homes
  • Accessory dwellings
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Mandatory utility hookup
  • Agricultural exemption
  • Driveway access
  • Building in a floodplain
  • Short-term rentals
  • Permit fees

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 Sunset Hills publishes no rule on the point, not that none exists. St. Louis County’s page lists the county offices to call.

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