Fountain Valley, CA Environmental Rules: Flood Zones (2026)

The floodplain overlay in § 21.14.040 applies to all areas of special flood hazard in the City of Fountain Valley. Those areas come from the FEMA Flood Insurance Study for Orange County and incorporated areas and its Flood Insurance Rate Map, both dated March 21, 2019, adopted by reference along with later amendments. The study and map are on file at City Hall, 10200 Slater Avenue. A special flood hazard area is one with a one percent or greater chance of flooding in any year, shown as zone A, AO, A1-A30, AE, A99 or AH.

Development permits are required before construction begins in these areas. Applications must show the proposed lowest-floor elevation in relation to mean sea level, the elevation of existing grade in zone AO, flood proofing elevations, an engineer's certification for nonresidential flood proofing, and how any watercourse will be altered. The planning and building director serves as floodplain administrator, grants or denies these permits, and checks that a project will not raise the base flood water surface more than one foot at any point.

Construction standards cover anchoring, flood-resistant materials, elevated utilities and flood openings of at least one square inch per square foot of enclosed area, with two openings on different sides and bottoms no higher than one foot above grade. Recreational vehicles must stay fewer than 180 consecutive days or be ready for highway use. Substantial improvement means work costing 50 percent or more of a structure's market value within five years. Until a regulatory floodway is adopted, no new development, including fill, is allowed in zones A1-A30 and AE unless it is shown to raise the base flood no more than one foot. Inside an adopted floodway, encroachments are prohibited without an engineer's no-rise certification.

The planning commission hears variances and appeals from the administrator's decisions, and an aggrieved person can appeal to the city council.