Solano County, CA zoning map, flood zone and property lines by address
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Towns in Solano County: Vallejo, Fairfield, Vacaville.
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's countywide study for Solano County has 188 FIRM panels, the newest effective August 2016; 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 Solano 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 Solano lot shows the same lines the county assessor draws. Solano County covers about 525,915 acres of land and 54,017 acres of water.
Mapped lines are approximate. The Solano County assessor keeps the parcel record (Solano County website); a licensed surveyor sets the true corners.
Zoning
Solano County zones its unincorporated land, and Vallejo, Fairfield, Vacaville each zone the land inside their 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 Solano 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. Solano County is soil survey area CA095, Solano County, California, last updated September 2026, on Web Soil Survey.
A new or changed septic system in Solano County needs a permit from the Solano County environmental health department (under the State Water Resources Control Board OWTS Policy).
Setbacks
Setbacks in Solano 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 Vallejo, Fairfield, Vacaville for land inside their limits.
Hazards that apply
- Storm surge. Solano 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 Solano lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Solano County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for Solano County has 188 panels, the newest effective August 2016. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Solano County?
Open the California map, type the address, and the parcel outline from the Solano 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 Solano County?
Zoning in Solano County is set by the county for unincorporated land and by each city (such as Vallejo, Fairfield) 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 Solano 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 Solano 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 Solano County?
Yes. A new or changed septic system in Solano County needs a permit from the Solano 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 CA095 (Solano County, California).
What can I build on 5 acres in Solano County?
Zoning in Solano County is set by the county for unincorporated land and each city inside its own limits (such as Vallejo, Fairfield). 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. See the Solano County website.
What are the residential setbacks in Solano County (2026)?
Setbacks in Solano 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. See the Solano County website.
Next to Solano County: Contra Costa County, Napa County, Sacramento County, Sonoma County, Yolo County.
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