Stormwater Management: Carson vs Los Angeles
How do stormwater management rules compare between Carson, CA and Los Angeles, CA?
Carson and Los Angeles have similar restriction levels.
Carson, CA
Los Angeles County
Carson adopts a Storm Water and Urban Runoff Pollution Control Ordinance as a co-permittee under the Los Angeles County Municipal Separate Storm Sewer System (MS4) NPDES permit. Non-stormwater discharges to the storm drain system (the Dominguez Channel watershed feeding LA Harbor) are prohibited and construction sites must implement Best Management Practices (BMPs). The city is one of ~85 LA County MS4 co-permittees subject to Regional Water Board orders implementing the federal Clean Water Act and the state Porter-Cologne Water Quality Control Act.
View full Carson rules →Los Angeles, CA
Los Angeles County
LAMC 64.72 (LID Ordinance, Ord. 183833) requires new development to manage stormwater runoff on-site through infiltration, bioretention, or capture systems. Priority projects must meet MS4 permit standards using the Development BMP Handbook. Projects disturbing 1+ acres need a state SWPPP. Grading permits are conditioned on stormwater compliance and a recorded covenant.
View full Los Angeles rules →Key Facts Comparison
| Fact | Carson | Los Angeles |
|---|---|---|
| Local citation | Carson Municipal Code Art. 4 Ch. 8 — Storm Water and Urban Runoff Pollution Control Ordinance | - |
| MS4 permit | LA County MS4 NPDES (Regional Water Board Order R4-2012-0175 et seq.) | - |
| Construction permit threshold | 1 acre or more disturbed area triggers Construction General Permit + SWPPP | - |
| State law | Federal Clean Water Act §402; Cal. Water Code §13000 et seq. (Porter-Cologne) | - |
| Receiving water | Dominguez Channel / Los Angeles Harbor | - |
| Code Section | - | LAMC 64.72 (LID Ordinance) |
| Requirement | - | On-site stormwater management |
| Hierarchy | - | Infiltration > bioretention > treatment |
| 1+ Acre Sites | - | State SWPPP required |
| Covenant | - | Recorded BMP maintenance agreement |
Highlighted rows indicate differences between cities.
Carson FAQ
Can I wash my car in my Carson driveway?
Residential car washing where soap runs into the street/storm drain is technically a prohibited non-stormwater discharge under CMC Art. 4 Ch. 8. The city generally focuses enforcement on commercial car washes and industrial discharges, but residents are encouraged to wash on lawn/gravel or use a commercial wash that routes water to the sanitary sewer.
Do I need a stormwater permit for a small home addition?
Projects disturbing less than 1 acre typically don't trigger the state Construction General Permit, but Carson still requires erosion and sediment controls during construction under the local ordinance and the LA County MS4 permit. Larger redevelopment projects (varies by use; 5,000-10,000 sq ft impervious is a common LA County threshold) trigger Low Impact Development post-construction BMPs.
Who enforces stormwater rules at the Carson refineries?
Industrial facilities like the Marathon and Phillips 66 refineries are covered by the State Water Board's Industrial General Permit (Order 2014-0057-DWQ) and discharge under individual NPDES permits — primary enforcement is the LA Regional Water Quality Control Board, not the City of Carson, though city code enforcement can act on illicit discharges entering the MS4.
Los Angeles 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 Los Angeles public works.
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