Fairfield, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard
- 1 foot above base flood elevation
- Zone AO rule
- 1 ft above FIRM depth number, or 3 ft
- Nonresidential option
- Floodproof watertight instead of elevating
- Certification
- Registered engineer or surveyor required
- Verification
- Building inspector confirms before compliance recorded
Summary
New construction and any 'substantial improvement' inside Fairfield's mapped flood hazard area must sit at least one foot above the base flood elevation at the lowest floor, including the basement, under Municipal Code § 8A.5.1.3. In Zone AO, the lowest floor must clear the FIRM's depth number by a foot, or three feet above the highest adjacent grade if no depth number is shown. A registered engineer or surveyor must certify the finished elevation.
New construction and substantial improvement of any structure shall have the lowest floor, including basement, elevated to at least one (1) foot above the base flood elevation. Nonresidential structures may meet the standards in section 8A.5.1.3(c). Upon completion of the structure the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor and verified by the building inspector that elevation requirements have been met. Notification of compliance shall be recorded as set forth in section 8A.4.2.3(a). New construction and substantial improvement of any structure in Zone AO shall have the lowest floor, including basement, elevated above the highest adjacent grade to at least one (1) foot above the depth number specified on the FIRM. If there is no depth number on the FIRM, the lowest floor, including basement, shall be elevated to at least three (3) feet above the highest adjacent grade.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4962673; v0 updated 2026-02-17).
Full Breakdown
3, part of Fairfield's Flood Damage Prevention chapter, sets the city's freeboard standard for anything built inside a mapped area of special flood hazard. 2. Zone AO, the shallow-flooding designation used where a defined channel doesn't exist and flood depths run one to three feet, gets its own rule: the lowest floor must sit at least one foot above the depth number printed on the Flood Insurance Rate Map, or, if the FIRM shows no depth number, at least three feet above the highest adjacent grade.
3(c): instead of elevating, they can be floodproofed watertight below the one-foot freeboard level, with a registered engineer or architect certifying the floodproofing design to the Director of Public Works. Whichever path is used, the finished elevation is not just self-reported. 3(a). 5.
Violations & Fines
Building below the required elevation, or without the certification the chapter demands, is enforced the same way as any other Chapter 8A violation: Section 8A.3.3 makes noncompliance a misdemeanor, and Section 8A.6.2 separately allows it to be charged as an infraction under Section 1.7, with the City Attorney able to sue to abate a noncompliant structure as a public nuisance at the City Manager's request.
Frequently Asked Questions
How high above flood level must I build in Fairfield?
Can a commercial building in Fairfield's flood zone skip the elevation requirement?
Who confirms my house was actually built high enough in Fairfield?
Sources & Official References
Other rules in Fairfield
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Flood Elevation Requirements in Nearby Cities
How other cities in Solano County handle flood elevation requirements.