St. Louis city, MO zoning map, flood zone and property lines by address
Free, no account. Or open the Missouri map and tap a lot.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA has 46 FIRM panels covering St. Louis city, the newest effective August 2025; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a St. Louis house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the Missouri county parcel layers (each county publishes its own), so a St. Louis lot shows the same lines the county assessor draws. St. Louis city covers about 39,499 acres of land and 2,850 acres of water.
Mapped lines are approximate. The St. Louis city county assessor keeps the parcel record (St. Louis city website); a licensed surveyor sets the true corners.
Zoning
In St. Louis city zoning is set by the city itself, an independent city outside any county. ParcelSheet shows the use code on the lot's parcel record and the municipality it sits in; the city planning office has the district, the uses it allows and the lot size it needs.
ADU and guest houses
Under Missouri's county planning and zoning law (Revised Statutes of Missouri Chapter 64), the city itself, an independent city outside any county can allow an accessory dwelling unit on a lot with a house. Whether a St. Louis lot can add one depends on its district; the city planning office has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. St. Louis city is soil survey area MO189, St. Louis County and St. Louis City, Missouri, last updated September 2026, on Web Soil Survey.
A new or changed septic system in St. Louis city needs a permit from the St. Louis city health department, or the county's other designated onsite authority (Missouri Department of Health and Senior Services onsite wastewater program).
Setbacks
Setbacks in St. Louis city come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the city planning office gives them for the lot's district.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a St. Louis lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in St. Louis city?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA has 46 flood map panels covering St. Louis city, the newest effective August 2025. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in St. Louis city?
Open the Missouri map, type the address, and the parcel outline from the St. Louis city county assessor shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in St. Louis city?
Zoning in St. Louis city is set by the city itself, an independent city outside any county. ParcelSheet shows the use code on the parcel record and names the municipality; the city planning office has the final word.
Can I build an ADU in St. Louis city?
Under Missouri's county planning and zoning law (Revised Statutes of Missouri Chapter 64), the city itself, an independent city outside any county can allow an accessory dwelling unit, and each sets its own rules. In St. Louis city ask the city planning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in St. Louis city?
Yes. A new or changed septic system in St. Louis city needs a permit from the St. Louis city health department, or the county's other designated onsite authority (Missouri Department of Health and Senior Services onsite wastewater program). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area MO189 (St. Louis County and St. Louis City, Missouri).
What can I build on 5 acres in St. Louis city?
Zoning in St. Louis city is set by the city itself, an independent city outside any county. The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the city planning office has the district and its rules. See the St. Louis city website.
What are the residential setbacks in St. Louis city (2026)?
Setbacks in St. Louis city come from the zoning code of the municipality the lot sits in: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the city planning office gives them for the district. See the St. Louis city website.
Next to St. Louis city: St. Louis County.
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