San Francisco County, CA zoning map, flood zone and property lines by address
Free, no account. Or open the California map and tap a lot.
Towns in San Francisco County: San Francisco.
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 70 FIRM panels covering San Francisco County, the newest effective March 2021; coastal V zones, where waves add to the flood, are mapped along its shore.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a San Francisco 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 California county parcel layers (each county publishes its own), so a San Francisco lot shows the same lines the county assessor draws. San Francisco County covers about 29,878 acres of land and 118,537 acres of water.
Mapped lines are approximate. The San Francisco County assessor keeps the parcel record; a licensed surveyor sets the true corners.
Zoning
San Francisco County zones its unincorporated land, and San Francisco zones the land inside its limits. ParcelSheet shows the use the county assessor lists for the lot and links the county planning department for the district, the uses it allows and the lot size it needs.
ADU and guest houses
Under California's Planning and Zoning Law (Government Code Title 7, Division 1, starting at section 65000), local governments can allow an accessory dwelling unit on a lot with a house. Whether a San Francisco lot can add one depends on its district; the county planning department 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. San Francisco County is soil survey area CA689, San Mateo County, Eastern Part, and San Francisco County, California, last updated September 2026, on Web Soil Survey.
A new or changed septic system in San Francisco County needs a permit from the San Francisco County environmental health department (under the State Water Resources Control Board OWTS Policy).
Setbacks
Setbacks in San Francisco County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the county zoning office gives them for the lot's district, and San Francisco for land inside its limits.
Hazards that apply
- Storm surge. San Francisco County has coastal V zones on its FEMA map, so storm surge reaches its shore. The county's evacuation zones are on its emergency management site; ParcelSheet shows the FEMA zone and the 3 ft sea level rise map at the lot.
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a San Francisco lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in San Francisco County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA has 70 flood map panels covering San Francisco County, the newest effective March 2021. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in San Francisco County?
Open the California map, type the address, and the parcel outline from the San Francisco 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 San Francisco County?
Zoning in San Francisco County is set by the county for unincorporated land and by each city (such as San Francisco) inside its own limits. ParcelSheet shows the use code the county assessor lists and links the office that sets the zoning; the planning office has the final word.
Can I build an ADU in San Francisco County?
Under California's Planning and Zoning Law (Government Code Title 7, Division 1, starting at section 65000), counties and cities can allow an accessory dwelling unit, and each sets its own rules. In San Francisco County ask the zoning 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 San Francisco County?
Yes. A new or changed septic system in San Francisco County needs a permit from the San Francisco County environmental health department (under the State Water Resources Control Board OWTS Policy). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area CA689 (San Mateo County, Eastern Part, and San Francisco County, California).
What can I build on 5 acres in San Francisco County?
Zoning in San Francisco County is set by the county for unincorporated land and each city inside its own limits (such as San Francisco). 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 planning office has the district and its rules.
What are the residential setbacks in San Francisco County (2026)?
Setbacks in San Francisco County come from the zoning code of the county, or of the city when the lot is inside city limits: 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 zoning office gives them for the district.
Next to San Francisco County: Alameda County, Contra Costa County, Marin County, San Mateo County.
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