Stormwater Management: Castaic vs Santa Monica
How do stormwater management rules compare between Castaic, CA and Santa Monica, CA?
Castaic has fewer restrictions than Santa Monica.
Castaic, CA
Los Angeles County
Unincorporated LA County falls under the LA County MS4 NPDES permit. The LACFCD operates one of the largest flood protection systems in the world, including 14 dams and 80,000+ catch basins. Low Impact Development standards apply to new construction. The district captures and infiltrates 270,000+ acre-feet annually.
View full Castaic rules →Santa Monica, CA
Los Angeles County
Santa Monica operates a stormwater utility under the municipal code with user fees on all parcels. The city promotes runoff conservation and sustainable management for water sustainability. LID and stormwater harvesting are strongly encouraged.
View full Santa Monica rules →Key Facts Comparison
| Fact | Castaic | Santa Monica |
|---|---|---|
| MS4 Permit | LA County NPDES | - |
| LID Required | For new development | - |
| LACFCD | 14 dams, 80,000+ catch basins | - |
| Annual Capture | 270,000+ acre-feet infiltrated | - |
| Stormwater Utility | - | User fee on all parcels |
| Runoff Conservation | - | SMMC Ch. 7.10 |
| LID | - | Encouraged for all development |
| Water Sustainability | - | Rainwater/stormwater reuse promoted |
Highlighted rows indicate differences between cities.
Castaic FAQ
What can go into storm drains in LA County?
Only stormwater. Illicit discharge of chemicals, wash water, paint, oil, or other pollutants is prohibited under Title 12 and the MS4 permit. Storm drains flow directly to rivers, ocean, and groundwater.
What are LID standards?
Low Impact Development standards require new development to capture and treat stormwater on-site through features like bioswales, permeable paving, cisterns, or rain gardens. They apply to new construction and major renovations.
How do I report illegal dumping into storm drains?
Call the LA County illegal dumping hotline at (888) 846-0800. For active spills or hazardous discharges, call 911 or the LA County Fire Department hazmat line.
Santa Monica FAQ
Do I need a stormwater plan for my project?
Generally required for new construction and major renovations that increase impervious surface area. Small residential projects may be exempt.
What is an illicit discharge?
Any non-stormwater substance entering the storm drain system, including paint, oil, chemicals, or sediment. Report violations to Santa Monica public works.
Compare other topics
See how Castaic and Santa Monica compare on other ordinance categories.
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