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Mendocino 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 Mendocino 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 chapter: Ch. 22.17, Floodplain Ordinance
Applies to: Unincorporated special flood hazard areas
FIS adoption date: June 16, 1992
Permit issuer: Floodplain Administrator (Building Official)
Fill compaction standard: 95% Standard Proctor Test
Violation penalty: Misdemeanor under Sec. 22.17.215

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 Mendocino 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 Mendocino County, CA on the FEMA flood map

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

Summary

Any construction or development in a Mendocino County special flood hazard area needs a development permit from the Floodplain Administrator, based on FEMA's Flood Insurance Study and rate maps for the unincorporated county.

These county ordinances apply to unincorporated areas of Mendocino County. Incorporated cities within the county may have their own rules that take precedence over county-level regulations.

This ordinance shall apply to all areas of special flood hazards within the unincorporated lands of Mendocino County... A development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in Section 22.17.210.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 75).

Full Breakdown

17, the Floodplain Ordinance, applies under Sec. ' Sec. 210 adopts by reference FEMA's Flood Insurance Study for unincorporated Mendocino County (dated June 16, 1992) and its accompanying Flood Insurance Rate Maps and Flood Boundary and Floodway Maps, kept on file at Planning and Building Services, 860 N. Bush Street, Ukiah. Sec. 305 requires a development permit before any construction or other development begins in a mapped special flood hazard area, with an application that must include a scaled site plan, spot or contour ground elevations, proposed water/sewer/utility locations, the base flood elevation from the FIRM, foundation design detail, and for fill-based foundations, compaction to 95% under the Standard Proctor Test.

The Building Official is designated Floodplain Administrator under Sec. 310, and Sec. 315 requires that official to confirm all other state and federal permits (including a Coastal Development Permit where the Coastal Act applies) are secured before work proceeds. Appeals of the Administrator's determinations go to the Board of Supervisors under Sec. 330.

Violations & Fines

Sec. 22.17.215 makes it unlawful to construct, locate, extend, convert, or alter any structure or land without full compliance with the floodplain ordinance, and declares that a violation, including breach of any permit condition or safeguard, is a misdemeanor. The Department of Planning and Building Services may take any lawful action necessary to prevent or remedy a violation. Under Sec. 22.17.230, where this ordinance conflicts with another county ordinance, easement, covenant, or deed restriction, whichever is more restrictive controls.

Frequently Asked Questions

Do I need a permit to build in a Mendocino County flood zone?

Yes. Sec. 22.17.305 requires a development permit from the Floodplain Administrator before any construction or development begins in an area of special flood hazard identified on FEMA's Flood Insurance Rate Maps for unincorporated Mendocino County.

What maps determine whether my property is in a flood hazard area?

Sec. 22.17.210 adopts FEMA's Flood Insurance Study for unincorporated Mendocino County, dated June 16, 1992, plus the accompanying Flood Insurance Rate Maps and Flood Boundary and Floodway Maps, which are kept on file at Planning and Building Services in Ukiah.

What happens if I build without a floodplain development permit?

Sec. 22.17.215 makes it a misdemeanor to construct, alter, or extend a structure in a flood hazard area without complying with Chapter 22.17, and authorizes Planning and Building Services to take lawful action to stop or remedy the violation.

Sources & Official References

[1]Mendocino County Code Ch. 22.17 (Municode)

Other rules in Mendocino County

Fence Regulations: Height LimitsSome Restrictions Erosion ControlSome Restrictions Stormwater ManagementSome Restrictions Flood Elevation RequirementsSome Restrictions Fence Regulations: Material RestrictionsSome Restrictions Fence Regulations: Retaining WallsSome Restrictions Fence Regulations: Fence Permit RequirementsSome Restrictions Animal Ordinances: MicrochippingSome Restrictions Animal Ordinances: Mandatory Spay/NeuterSome Restrictions

All Mendocino County rules

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