Erosion Control: Daly City vs South San Francisco
How do erosion control rules compare between Daly City, CA and South San Francisco, CA?
South San Francisco has fewer restrictions than Daly City.
Daly City, CA
San Mateo County
Erosion and sediment control on Daly City construction sites is required by the Bay Area Municipal Regional Stormwater Permit (Order R2-2015-0049 Provision C.6), the statewide Construction General Permit (Order 2009-0009-DWQ) for projects disturbing 1 acre or more, and the California Building Code Appendix J grading provisions adopted in Title 12.
View full Daly City rules →South San Francisco, CA
San Mateo County
San Mateo County Planning & Building Department requires submittal of an Erosion and Sediment Control Plan prior to issuance of any demolition, grading, or building permit that involves site disturbance. Standard BMPs include silt fencing, straw wattles, erosion control blankets, stabilized construction entrances, and covered stockpiles. Wet-season work (October 1 - April 30) triggers additional inspection requirements and may be restricted on steep slopes. SWPPP required for sites 1+ acre.
View full South San Francisco rules →Key Facts Comparison
| Fact | Daly City | South San Francisco |
|---|---|---|
| Wet season | October 1 - April 30 (heightened BMP requirements) | - |
| CGP threshold | 1 acre disturbed (or common plan of development) | - |
| Local authority | MRP Provision C.6 + CBC Appendix J grading | - |
| Required BMPs | Silt fence, wattles, inlet protection, slope stabilization | - |
| SWPPP | Required if CGP applies; signed by QSD | Sites 1+ acre |
| ESCP Required | - | All ground-disturbing work |
| Wet Season | - | Oct 1 to Apr 30 |
| Stabilization | - | Within 14 days |
| Final Cover | - | 70% vegetation |
Highlighted rows indicate differences between cities.
Daly City FAQ
Does a small backyard project need erosion control?
Yes - any soil-disturbing work that could send sediment to a gutter or storm drain is subject to MRP construction-site BMPs. The Engineering or Building Division typically requires at minimum a silt fence or fiber roll along the downhill edge and protection at the nearest storm-drain inlet.
When is wet-season erosion control required?
Daly City follows the Bay Area MRP wet-season window of October 1 through April 30. Exposed slopes must be stabilized (mulch, hydroseed, erosion mat, or equivalent) before October 1 each year unless active grading is approved.
Do I need a SWPPP?
Only if your project disturbs 1 acre or more (including phased projects under a common plan of development). Smaller sites still need an erosion-and-sediment-control plan but not a state-filed SWPPP.
South San Francisco FAQ
Do I need erosion controls for a small addition?
Any project that disturbs soil — even a small addition or trench for utilities — requires basic BMPs like silt fence at the downslope edge and inlet protection on nearby storm drains. The County ESC Manual shows simplified standards for residential-scale projects. Your building plans must include an ESC sheet.
What happens if a storm washes sediment off my site into a creek?
You face enforcement from both the County (stop-work, fines) and the SF Bay RWQCB, which can assess up to $25,000/day under the Porter-Cologne Act. You'll also be responsible for cleanup costs and potential CDFW notification if fish habitat is affected. Maintain BMPs before every rain event.
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