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

Lake County Code Chapter 25, the Floodplain Management Ordinance, applies to all areas of special flood hazard in the unincorporated county as mapped on the Flood Insurance Rate Maps and Flood Boundary and Floodway Maps adopted from the September 30, 1992 Flood Insurance Study (originally dated October 17, 1978), on file with the Lake County Flood Control and Water Conservation District at 255 North Forbes Street, Lakeport. Under Sec. 1, any development or placement of a structure in a Special Flood Hazard Area must conform to the chapter, and no development permit may be issued without review by the Floodplain Administrator, a role assigned by Sec.

2 to the Director of the Flood Control and Water Conservation District. That review checks under Sec. 3 that the site is reasonably safe from flooding, that state and federal permits are in hand, and that the project will not raise the base flood elevation more than one foot at any point when combined with other development. Sec. 1 sets the construction standards themselves: residential construction must have its lowest floor, including any basement, elevated at least one foot above the base flood elevation in an A zone and in all other zones, or elevated to the FIRM depth number plus one foot in an AO zone; nonresidential buildings may instead be floodproofed watertight below that elevation and certified by a registered civil engineer or licensed architect.

Enclosed areas below the lowest floor used only for parking, access or storage need at least two openings totaling one square inch of net area per square foot of enclosed space, with the bottom of each opening no higher than one foot above grade, to let floodwater equalize automatically. Decisions of the Floodplain Administrator can be appealed to the Board of Supervisors within fifteen calendar days under Sec. 5, with a public hearing decided within forty-five days of the hearing's close.