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San Marcos, CA Environmental Rules: Stormwater Management (2026)

Significant Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Governing chapter
Municipal Code Ch. 14.15
Illegal discharge
Prohibited unless NPDES-permitted
Construction cleaning
Required before each Wet Season
Spill notification
County Hazmat notified within 24 hours
Charge level
Misdemeanor, chargeable as infraction

Summary

San Marcos bans any illegal discharge into its storm drain system under Municipal Code Chapter 14.15. Businesses, construction sites and residents must keep pollutants such as wash water, pool chemicals, paint and pet waste out of gutters and storm drains, and violators face misdemeanor charges with fines up to $1,000 per day.

Illegal or Illicit Discharges to the Storm Water Conveyance System are prohibited, except that the following discharges are exempt from the prohibition set forth above: (a)Any discharge regulated under a NPDES Permit issued to the Discharger and administered by the State of California pursuant to Chapter 5.5, Division 7 of the California Water Code, provided that the Discharger is in compliance with all requirements of the Permit and other applicable laws and regulations. (b)Any discharge which the Director and the Regional Water Quality Control Board determine is necessary for the protection of the public health and safety.

View official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).

Full Breakdown

15, the Storm Water Management and Discharge Control ordinance, prohibits any "Illegal or Illicit Discharge" to the city's Storm Water Conveyance System except discharges covered by a valid NPDES permit or those the Director and Regional Water Quality Control Board find necessary for public health and safety (Sec. 030). Establishing or maintaining an illegal connection to the storm drain system is separately banned under Sec. 040. 050 requires every discharger whose activity may add pollutants to storm water to implement Best Management Practices to the Maximum Extent Practicable, and lists prohibited discharges by name, including wash water from vehicle or equipment cleaning, chlorinated pool or fountain water, grease and food-processing waste, and sediment or pet waste.

Industrial, commercial and construction operators may be required to prepare a Storm Water Pollution Prevention Plan (SWPPP) documenting site controls, employee training and spill response procedures. Property owners along a watercourse must keep it free of trash and debris and may not modify its natural flow or build within 30 feet of a creek centerline (Sec. 060). Authorized Enforcement Officials may inspect premises, take samples, photograph violations and order corrective action plans (Sec. 070), and any person discovering a significant spill must notify the County's Hazardous Materials Management Division within 24 hours.

Violations & Fines

A violation of Chapter 14.15 is a misdemeanor, though the City may instead charge it as an infraction at its discretion (Sec. 14.15.080). Penalties follow Chapter 1.12 of the Municipal Code, and the ordinance separately authorizes civil actions, cease and desist orders, stop work orders, and permit suspension or revocation for continuing violations. Each day a violation continues is treated as a separate offense, and violations are also declared a public nuisance subject to abatement.

Frequently Asked Questions

Can I wash my car in the driveway in San Marcos?
Non-commercial residential vehicle washing is listed as an exception to the illegal discharge rules, but the city still requires you to minimize water and detergent use and, where feasible, direct wash water to landscaped or pervious areas rather than the street or storm drain under Sec. 14.15.050.
Who enforces San Marcos stormwater rules?
An Authorized Enforcement Official designated by the Director administers Chapter 14.15, with authority to inspect properties, take samples, photograph violations and issue correction notices under Sec. 14.15.070.
What happens if I drain a swimming pool into the street?
Discharging pool or fountain water containing chlorine, algaecide or filter backwash into the storm drain system is listed as an illegal discharge under Sec. 14.15.050(a) unless it is dechlorinated and pollutant-free, and it can be prosecuted as a misdemeanor under Sec. 14.15.080.

Sources & Official References

Other rules in San Marcos

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