Monterey County, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard
- 1 foot above base flood elevation
- Zone AO variant
- 1-2 feet above adjacent grade
- Certification
- Licensed surveyor or civil engineer
- Administered by
- HCD Floodplain Administrator
- Flood vents
- 1 sq in per sq ft enclosed area
Summary
Monterey County Code Section 16.16.050(C) requires new construction and substantial improvements in Special Flood Hazard Areas to elevate the lowest floor, including any basement, at least one foot above the base flood elevation shown on the FIRM. The Housing and Community Development Department's Floodplain Administrator verifies compliance through elevation certification by a licensed surveyor or engineer.
C.Elevation and Floodproofing.1.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. Non-residential structures may meet the standards in Section 16.16.050.C.3. Upon completion of the structure the elevation of the lowest floor, including basement, shall be certified by a registered civil engineer or surveyor or verified by the County Building Inspector that elevation requirements have been met. Notification of compliance shall be recorded as set forth in Section 16.16.040.G.1.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 56).
Full Breakdown
16, Regulations for Floodplains, implements the county's National Flood Insurance Program obligations and applies wherever a Special Flood Hazard Area (SFHA) is mapped on the Flood Insurance Rate Map (FIRM), coastal and inland alike. 050(C)(1) requires that '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,' with compliance certified by a registered civil engineer or surveyor, or verified by the County Building Inspector, once the structure is complete.
050(C)(2) instead requires the lowest floor to sit at least one foot above the highest adjacent grade, or two feet if the FIRM shows no depth number. 050(C)(3), watertight to at least one foot above the base flood elevation and certified by a registered engineer or architect. 050(D) additionally requires enclosed areas below the lowest floor, such as parking or storage space, to include flood vents sized to at least one square inch of opening per square foot of enclosed area, so hydrostatic pressure cannot collapse the walls.
Attached garages built with the floor slab below the base flood elevation must be built of flood-resistant materials up to that same one-foot freeboard mark. 040 and can require a Letter of Map Revision based on Fill (LOMR-F) where a site has been filled above the base flood elevation.
Violations & Fines
The County, through the Floodplain Administrator, may take remedial action against Chapter 16.16 violations as specified in Section 16.16.030(C), and inspections under Section 16.16.040(M) can require correction before final approval. Because floodplain development also requires a building or floodplain development permit, uncertified or under-elevated construction can be held up at the lowest-floor inspection stage, before vertical construction continues, until a licensed surveyor or engineer confirms the one-foot freeboard has been met.
Frequently Asked Questions
How high above flood level must a new home be built in Monterey County?
Can a non-residential building in Monterey County use floodproofing instead of elevation?
What if my Monterey County lot is in Zone AO instead of a numbered flood zone?
Sources & Official References
Other rules in Monterey County
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