San Marcos, CA Environmental Rules: Erosion Control (2026)

130 makes an Interim Erosion Control Plan a required part of every grading plan submittal, not an afterthought added once work starts. The Engineer of Record must estimate the cost of installing and maintaining every interim erosion and sediment control measure so the City can set a bond, and the plan itself must cover eight categories: reducing erodible soil exposure ahead of storms, including consulting the National Weather Service and having controls in place at least 24 hours before a forecast rain event, erosion control measures such as hydroseeding and preserved vegetation, flow control measures like gravel bag dikes and fiber rolls, diversion of runoff and nuisance flow away from the construction area, sediment control devices including silt fences and desilting basins, confirmation of coverage under the State of California Construction General Permit, and a waste management component covering spill prevention and a 24-hour emergency contact.

The plan must also identify a 24-hour emergency telephone contact, be signed and sealed by the preparing professional, and describe the access plan for maintaining controls in wet weather. Once approved, maintenance duties continue through the rainy season: removable protection devices must be in place at the end of each working day whenever the five-day rain probability forecast exceeds 40 percent, silt and debris must be cleared from check berms and desilting basins after every storm, and graded areas around the tract perimeter must drain away from slope faces by day's end.

If a contractor or owner fails to maintain the system, the Administrative Authority can perform emergency maintenance and bill the owner, plus revoke the Grading permit until an approved system is reinstalled.