Sunnyvale, CA Environmental Rules: Flood Elevation Requirements (2026)
Key Facts
- Freeboard margin
- Base flood elevation plus one foot
- Applies to
- Detached garages, accessory buildings, manufactured homes
- Garage size cap
- 600 sq ft, one story, in SFHA
- Certification required
- CA-licensed surveyor or civil engineer
- Standard for other buildings
- ASCE 24 via CA Building Standards Code
- Penalty
- Misdemeanor: up to $1,000 fine, 6 months jail
Summary
Sunnyvale's floodplain code adds a one-foot freeboard margin above FEMA's base flood elevation for the structures it regulates directly. Detached garages and accessory storage buildings permitted below the base flood elevation must still have their mechanical, plumbing, and electrical systems elevated to at least one foot above it, and manufactured homes citywide must have their lowest floor set at base flood elevation plus one foot under Chapter 16.62.
Detached Garages and Accessory Storage Structures. Detached garages and accessory storage structures used only for parking or storage are permitted below the base flood elevation provided the garages and accessory storage structures: (1) Are one story and not larger than 600 square feet in area when located in special flood hazard areas. (2) Are anchored to resist flotation, collapse or lateral movement resulting from flood loads. (3) Have flood openings in accordance with the building code. (4) Have flood damage-resistant materials used below the base flood elevation. (5) Have mechanical, plumbing and electrical systems, including plumbing fixtures, elevated to or above the base flood elevation plus one foot.
Full Breakdown
300(b) allows detached garages and accessory storage structures used only for parking or storage to sit below the base flood elevation, but only if they are one story, no larger than 600 square feet when located in a special flood hazard area, anchored against flotation and lateral movement, fitted with code-compliant flood openings, built of flood damage-resistant material below the base flood elevation, and have every mechanical, plumbing, and electrical system, including plumbing fixtures, elevated to or above the base flood elevation plus one foot.
That extra foot is Sunnyvale's local freeboard margin above the FEMA-mapped base flood elevation. 330(e) applies the identical plus-one-foot standard to homes in existing manufactured home parks. Mechanical equipment and outside appliances serving those homes must independently clear the lowest floor, or the home's lowest horizontal member, by another foot, unless the equipment is designed and installed to resist flooding up to that elevation. 130.
Violations & Fines
A structure built or elevated below the required base flood elevation plus one foot without the surveyor or engineer certification required by these regulations is presumed a violation under Section 16.62.160, exposing the owner to misdemeanor penalties of up to $1,000 and six months in county jail, since Chapter 16.62 is excluded from the code's infraction list. Insurance consequences follow too: constructing below the required elevation under a variance can raise flood-insurance premiums as high as $25 per $100 of coverage.
Frequently Asked Questions
How much higher than the base flood elevation must a Sunnyvale structure be built?
Can a garage be built below the base flood elevation in Sunnyvale?
Who certifies the elevation of a new structure's lowest floor?
Sources & Official References
Other rules in Sunnyvale
California rules heatmap·Compare Sunnyvale to another location·View the California environmental rules overview
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Flood Elevation Requirements in Nearby Cities
How other cities in Santa Clara County handle flood elevation requirements.