Building near the coast or a creek in Hillsborough, California
Hillsborough has no coastal or creek-setback zone in its code; building near a creek is governed by the town's floodplain rules. In a FEMA-mapped flood hazard area you need a floodplain development permit, the lowest floor must be at least 1 foot above base flood elevation, and building in a floodway is barred unless an engineer shows no rise in flood levels.
| Permit in flood hazard area | Floodplain development permit [2] |
| Lowest floor elevation | At least 1 ft above base flood elevation [3] |
| Floodway | No encroachment without engineer's no-rise certification [4] |
| Flood maps | FEMA FIRMs effective Oct. 16, 2012 (and revisions) [6] |
| Standard side/rear setback | 20 ft [8] |
No shoreline or creek-setback ordinance
Hillsborough's code has no shoreland zone, coastal development permit program or dedicated creek setback in the documents we reviewed. Building near a creek is controlled mainly by the town's floodplain management chapter, plus the ordinary zoning setbacks (20 feet from side and rear lot lines) [8] and design review. The code defines a "watercourse" broadly to include creeks, streams, washes and channels that carry water at least periodically [5].
Flood hazard areas
The floodplain chapter applies to all special flood hazard areas in town [1], as mapped on FEMA's Flood Insurance Rate Maps effective October 16, 2012 and later revisions [6]. Before any construction or other development in a mapped flood hazard area, you need a development permit from the floodplain administrator [2]. Applications show elevations of the lowest floor, any fill, and the extent to which a watercourse would be altered.
Construction standards
New homes and substantial improvements in flood hazard areas must be anchored against flotation and collapse [7] and must have the lowest floor, including basements, at least 1 foot above the base flood elevation, certified by an engineer or surveyor [3]. If a creek is altered or relocated, the town must notify adjacent communities and the California Department of Water Resources and make sure the altered channel keeps its flood-carrying capacity [9].
Floodways
In a designated floodway (the creek channel and adjacent land that carries flood flows), fill, new construction and substantial improvements are prohibited unless an engineer or architect certifies they won't raise the base flood elevation at all [4].
Other agencies
Creek work such as bank stabilization, removing riparian vegetation, culverts or building next to a creek can also need state and federal approvals from state fish and wildlife, regional water quality and federal Army Corps of Engineers regulators. The town posts a countywide creek-permitting guide, but it dates from 1996.
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Next steps
- Check FEMA's flood maps or ask Public Works (1600 Floribunda Ave.) whether your lot is in a special flood hazard area or floodway.
- If it is, apply for a floodplain development permit with plans showing lowest-floor elevation, fill and any creek alteration.
- For work in or next to a creek, contact the state fish and wildlife agency, the San Francisco Bay Regional Water Quality Control Board and the Army Corps of Engineers early.
- Submit the project for design review and building permits through Building and Planning, (650) 375-7411.
Common questions
- Are there creek or shoreline setbacks in Hillsborough, California?
- Hillsborough has no coastal or creek-setback zone in its code. Building near a creek is governed by the town's floodplain rules.
- Do I need a floodplain permit in Hillsborough, California?
- Yes, in a FEMA-mapped flood hazard area you need a floodplain development permit. Check FEMA's flood maps or ask Public Works whether your lot is in a special flood hazard area.
- How high must the floor be in a flood zone in Hillsborough, California?
- The lowest floor must be at least 1 foot above base flood elevation.
- Can I build in a floodway in Hillsborough, California?
- No, not unless an engineer shows no rise in flood levels (a no-rise certification).
California rules for building near the coast and creeks
California has no statewide shoreland setback. Near water, two state laws matter most.
The coastal zone (Coastal Act, Pub. Res. Code §30000 et seq.):
- Almost any development in the coastal zone needs a coastal development permit (CDP) (§30600). "Development" is broad: buildings, additions, grading, lot splits, removing major vegetation, and changes in intensity of use (§30106).
- The zone generally runs about 1,000 yards inland from mean high tide (up to 5 miles in some habitat areas, less in some cities). San Francisco Bay is excluded; BCDC regulates it (§30103).
- Where a city or county has a Local Coastal Program (LCP) certified by the Coastal Commission, it issues the CDP (§30519). Otherwise the Commission does.
- Local approvals can be appealed to the Coastal Commission for projects between the sea and the first public road, within 300 ft of a beach or the mean high tide line, within 100 ft of a wetland, estuary or stream, or within 300 ft of a coastal bluff (§30603).
- Some improvements to existing homes and repairs are exempt (§30610), with exceptions set by regulation.
Creeks, streams and lakes statewide: you must notify the Department of Fish and Wildlife before work that diverts or blocks a stream, changes its bed, channel or bank, or puts material into it (Fish & Game Code §1602), even for streams that are dry part of the year. CDFW may require a Lake or Streambed Alteration Agreement.
Cities and counties often add their own creek setbacks or riparian buffers.
What the ordinance says
- Sec. 15.44.020(A), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
This chapter applies to all areas of special flood hazards within the jurisdiction of the town.
- Sec. 15.44.030(A), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
A development permit shall be obtained before any construction or other development begins within any area of special flood hazard established in Section 15.44.020 B. of this chapter.
- Sec. 15.44.040(A)(3)(a), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
Residential construction, new or substantial improvement, shall have the lowest floor, including basement, elevated to at least one foot above the base flood elevation, as determined by the community.
- Sec. 15.44.040(D)(1), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
Prohibit encroachments, including fill, new construction, substantial improvement, and other new development unless certification by a registered professional engineer or architect is provided demonstrating that encroachments shall not result in any increase in the base flood elevation during the occurrence of the base flood discharge.
- Sec. 15.44.010 (definitions), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
"Watercourse" means a lake, river, creek, stream, wash, arroyo, channel or other topographic feature on or over which waters flow at least periodically.
- Sec. 15.44.020(B), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
The areas of special flood hazard identified by the Federal Insurance Administration (FIA) of the Federal Emergency Management Agency (FEMA) in the Flood Insurance Study (FIS) dated effective October 16, 2012, and accompanying Flood Insurance Rate Maps (FIRMs) and Flood Boundary and Floodway Maps (FBFMs), dated effective October 16, 2012, and all subsequent amendments and/or revisions, are hereby adopted by reference and declared to be a part of this chapter.
- Sec. 15.44.040(A)(1), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
All new construction and substantial improvements shall be adequately anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic or hydrostatic loads, including the effects of buoyancy.
- Sec. 17.24.020(C), Municipal Code Title 17 Ch. 17.24 Required Setback Areas, p. 1
The interior setback area is that twenty-foot wide strip of land that is bounded on one side by a lot line that is not a street line and on the other side by a parallel line located on the lot and twenty feet distant from the lot line, such parallel line continuing until either end of it abuts a lot line.
- Sec. 15.44.030 (watercourse alteration), Municipal Code Title 15 Ch. 15.44 Floodplain Management, p. 1
Assure that the flood-carrying capacity within the altered or relocated portion of such watercourse is maintained.