San Bernardino County, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard, AE/A1-30/AH zones
- 1 foot above base flood elevation
- Freeboard, Shaded X zone
- 1 foot above natural grade
- Flood vent sizing
- 1 sq in per sq ft of enclosed area
- Max detached garage below BFE
- 600 sq ft, one story
- RV floodplain stay limit
- Fewer than 180 consecutive days
- Variance authority
- Planning Commission, County Code § 82.14.060
- Insurance notice
- Premiums up to $25 per $100 coverage
Summary
New construction and substantial improvements inside San Bernardino County's mapped floodplains must raise their lowest floor above the base flood elevation under County Code § 82.14.050(d). AE, A1-30 and AH zones require one foot of freeboard above BFE; AO, A and Shaded X zones use grade-based formulas, and every elevation must be certified on a FEMA Elevation Certificate.
(d) Elevation and Flood-proofing. (1) Residential Structures. New construction and substantial improvement of any residential structure shall include having the lowest floor (including basement): (A) In AE, A1-30, AH Zones, elevated one foot above the base flood elevation. (B) In an AO zone, elevated above the highest adjacent grade to a height one foot above the depth number specified in feet on the FIRM, or elevated at least two feet above the highest adjacent grade if no depth number is specified. (C) In an A Zone, without BFE's specified on the FIRM, elevated two feet or more above the natural pre-development highest adjacent grade. (D) In a Shaded X Zone (the 100- to 500-year floodplain), elevated one foot above the natural pre-development highest adjacent grade. Upon completion of the structure, the elevation of the lowest floor (including basement) shall be certified by a registered civil engineer or licensed land surveyor to be properly elevated above the floodplain elevation at the time of certification. The certification shall be provided on the current FEMA Elevation Certificate form to the Building Official.
Full Breakdown
The Floodplain Safety Review Area standards in § 82.14.050 start with anchoring: every new or substantially improved structure, including manufactured homes, must be anchored to its foundation to prevent flotation, collapse or lateral movement from hydrodynamic and hydrostatic loads (§ 82.14.050(a)). Materials installed below the base flood elevation must resist flood damage, and utilities must be located or designed to keep water out during flooding (§ 82.14.050(b)).
The freeboard requirement itself sits in § 82.14.050(d)(1): a new or substantially improved residential structure's lowest floor, including any basement, must be elevated one foot above the base flood elevation in AE, A1-30 and AH zones; in an AO zone it must clear the FIRM's depth number by one foot, or two feet above the highest adjacent grade if no depth number is shown; in an A zone with no BFE on the FIRM it must sit two feet above the natural pre-development highest adjacent grade; and in a Shaded X (100- to 500-year) zone it needs one foot above that same natural grade. A registered civil engineer or licensed surveyor must certify the finished elevation on the current FEMA Elevation Certificate, filed with the Building Official. Nonresidential buildings may instead be dry flood-proofed watertight to the same elevation under § 82.14.050(d)(2), certified by an engineer or architect to the Floodplain Administrator.
Enclosed areas below the lowest floor need flood-vent openings sized at one square inch per square foot of enclosed area, with the lowest opening no higher than one foot above grade (§ 82.14.050(d)(3)). Small detached garages and accessory structures of 600 square feet or less may keep a floor below BFE if flood-resistant and anchored (§ 82.14.050(d)(4)). Floodways bar any encroachment, including fill, unless an engineer certifies no rise in base flood levels (§ 82.14.050(h)). Recreational vehicles may stay in the 100-year floodplain only if present under 180 consecutive days or licensed and ready for highway use (§ 82.14.050(i)).
Violations & Fines
Section 82.14.060 lets the Planning Commission grant a variance only on a showing of hardship tied to the land itself, never in a floodway if it would raise flood levels. Any variance to build below the base flood elevation triggers a written notice that flood-insurance premiums can run as high as $25 per $100 of coverage, and the Floodplain Administrator must record a Notice of Condition against the parcel's chain of title.
Frequently Asked Questions
How high above the base flood elevation must a new home be built?
Can a garage be built below the base flood elevation?
What if my flood zone has no base flood elevation on the map?
Can I get a variance from these elevation standards?
Sources & Official References
Other rules in San Bernardino County
California rules heatmap·Compare San Bernardino County to another location·View the California environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.