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Solano County, CA Environmental Rules: Flood Zones (2026)

Significant Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

FEMA flood zone rules in Solano County, CA, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.

Key Facts

Governing map: Feb. 2, 1982 Flood Insurance Study/FIRM
Administrator: Director, Dept. of Resource Management
Trigger: Any building, zoning, use or grading permit
Penalty: Misdemeanor plus possible civil injunction
Appeal path: Variance to administrator, then Board of Supervisors

FEMA Flood Zone Lookup

FEMA assigns every parcel in the U.S. a flood-hazard designation on its Flood Insurance Rate Maps (FIRMs). Zones starting with A or V are high-risk Special Flood Hazard Areas where federally backed mortgages require NFIP flood insurance. Zone X indicates moderate-to-minimal risk, where insurance is optional but often recommended. Your specific zone determines insurance cost, build elevation, and permit requirements in Solano County, CA.

Zone	What it means	NFIP required?
A	High-risk flood area; 1% annual chance flood, no detailed analysis.	Yes
AE	High-risk; same as A but with established Base Flood Elevations.	Yes
AH	High-risk shallow flooding (1-3 ft), usually ponding.	Yes
AO	High-risk shallow flooding (1-3 ft) with sheet flow on sloping terrain.	Yes
V	High-risk coastal zone subject to wave action (no BFE).	Yes
VE	High-risk coastal zone with wave action and established BFEs.	Yes
X (shaded)	Moderate risk; between the 1% and 0.2% annual chance flood.	Recommended
X	Minimal risk; outside the 0.2% annual chance floodplain.	No

Look up Solano County, CA on the FEMA flood map

FEMA maps update periodically; verify zone before buying flood insurance or building.

Summary

Any building, zoning, use, or grading permit application in unincorporated Solano County gets checked against FEMA's Flood Insurance Rate Maps before it's issued. If the site falls inside a mapped special flood hazard area, Section 12.2-41 routes the application to the county's floodplain administrator for mandatory review under Chapter 12.2 before construction can proceed.

City-specific rules exist: Vacaville, Vallejo, and Fairfield have their own flood zones rules that differ from Solano County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

This ordinance shall apply to all special flood hazard areas within the jurisdiction of the County of Solano. ... Upon application for a building, zoning, use or grading permit, the Solano County building inspector, Director of Resource Management, or other employee responsible (responsible employee) for review of such applications, shall review the submitted application and plans and determine whether or not the site of the proposed structure is within any special flood hazard area established in Section 12.2-31. If the site of the proposed structure or development lies within any special flood hazard area, the application and plans shall be referred to the floodplain administrator for review as specified in Section 12.1-43. ... No structure or land shall hereafter be constructed, located, extended, converted, or altered without full compliance with the terms of this chapter and other applicable regulations. Violations of the provisions of this chapter by failure to comply with any of its requirements ... shall constitute a misdemeanor.

Source: Solano County Code Chapter 12.2 - Flood Damage PreventionView official code

Official source re-checked September 8, 2026: no newer edition of the code had been published (publisher’s edition: current through Ordinance 1868, passed April 9, 2026).

Full Breakdown

2-31 and kept on file at the Office of Resource Management. 2-40 designates the Director of the Department of Resource Management as floodplain administrator, with authority to grant or deny permits under the chapter. 2-41, every building, zoning, use, or grading permit application is checked against the mapped special flood hazard areas; if the site falls inside one, the application and plans go to the floodplain administrator for review before any permit issues, while sites outside the mapped zone follow ordinary permitting. 2-42 lets the administrator demand scaled plans showing existing and proposed elevations, drainage, fill and structures, plus the proposed elevation of the lowest floor and any floodproofing elevation.

2-33 makes the stricter of this chapter or any conflicting easement, covenant, or deed restriction control. 2-60(c) lets the Board of Supervisors hear appeals from the administrator's decisions.

Violations & Fines

Section 12.2-32 makes any failure to comply with the chapter's requirements, including violated permit conditions and safeguards, a misdemeanor, and the Board of Supervisors can also pursue civil remedies such as an injunction to stop or undo unauthorized floodplain development. Because compliance is checked at the permit stage, building without the required floodplain review can hold up final sign-off until the structure is brought into conformance.

Frequently Asked Questions

Do I need special approval to build in a Solano County flood zone?

Yes. Under Section 12.2-41, the county checks every building, zoning, use, and grading permit against the mapped special flood hazard areas. If your parcel sits inside one, the floodplain administrator, the Director of Resource Management, must review the application under Chapter 12.2 before any permit is issued.

What happens if I develop flood hazard land without going through this review?

Section 12.2-32 makes it a misdemeanor to construct, locate, extend, convert, or alter any structure or land without full compliance with Chapter 12.2. The Board of Supervisors can also seek a civil injunction to stop or reverse unauthorized work in a special flood hazard area.

Can I appeal a floodplain permit denial?

Yes. Section 12.2-60 lets you apply to the floodplain administrator for a variance, explaining the hardship you would suffer without it. If the administrator denies the request, Section 12.2-60(c) lets you appeal that decision to the Solano County Board of Supervisors.

Sources & Official References

[1]Solano County Code Ch. 12.2 (Flood Damage Prevention)

Other rules in Solano County

Stormwater ManagementSome Restrictions Erosion ControlSome Restrictions Flood Elevation RequirementsSome Restrictions Defensible SpaceSome Restrictions Fence Regulations: Retaining WallsSome Restrictions Animal Ordinances: Veterinary Clinic ZoningSome Restrictions Animal Ordinances: MicrochippingHeavy Restrictions Fire Regulations: Wildfire ZonesSignificant Restrictions Invasive Plant Rules: Prohibited SpeciesLight Restrictions Short-Term Rentals: Host Presence RuleSome Restrictions

All Solano County rules

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Flood Zones in Cities Across Solano County

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