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Butte County, CA Environmental Rules: Stormwater Management (2026)

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

Key Facts

Core prohibition
Illicit non-stormwater discharge banned (§ 50-11)
Strict liability
No negligence or intent required (§ 50-16)
Exempt discharges
Car washing, pool drainage, footing drains (§ 50-12)
Irrigation runoff window
Scheduled 2:00-10:00 a.m. only (§ 24-116)
Appeal deadline
30 days, fee under § 3-43(1) (§ 50-33)
Enforcement agency
Public Works Administrator, under Chapter 41
Applies to
Unincorporated Small MS4 permit area only (§ 50-6)

Summary

Chapter 50 of the Butte County Code bans any 'illicit discharge' of non-stormwater materials into the County storm drain system, natural surface waters, or watercourses in the unincorporated Small MS4 permit area (Section 50-11). A narrow list of exemptions covers things like residential car washing and dechlorinated pool water (Section 50-12), but liability for a prohibited discharge is strict, no negligence or intent required (Section 50-16).

City-specific rules exist: Chico has its own stormwater management rules that differ from Butte County's county-level regulations. If you live in Chico, check the city-specific page instead.

Except as provided in Section 50-12, it shall be unlawful for any person to make or cause to be made an illicit discharge of any materials, including, but not limited to, pollutants or waters containing any pollutants, other than stormwater into the County storm drain system, natural surface waters, or watercourses.

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 61).

Full Breakdown

Adopted as the 'Stormwater Ordinance' (Section 50-1) to satisfy the federal Clean Water Act and the state Porter-Cologne Water Quality Control Act, Chapter 50 applies to every discharger in the unincorporated County within the Small MS4 General Permit jurisdictional area (Sections 50-2, 50-3, 50-6). Section 50-11 makes it unlawful to cause an illicit discharge, meaning any material other than stormwater, into the County storm drain system, natural surface waters, or watercourses. under the landscaping standards of Section 24-116. The Administrator (the Director of Public Works or a designee) can revoke any exemption by written notice if a discharge threatens water quality or public safety (Section 50-13).

Illicit connections to the storm drain system or watercourses are separately prohibited and must be removed on the Administrator's order (Section 50-15), and Section 50-16 makes clear that a violation occurs regardless of the discharger's negligence or intent. Section 50-17 bars throwing or leaving refuse, rubbish, or litter where it could become a pollutant to the storm system, on top of the general waste disposal prohibition. Violations are enforced under County Code Chapter 41 (Section 50-27), are deemed a public nuisance subject to abatement at the violator's expense (Section 50-28), and can expose a discharger to civil and criminal penalties under the Clean Water Act and Porter-Cologne Act as well as County remedies (Section 50-30).

Anyone who receives a written notice of violation from the Administrator may appeal to the Clerk of the Board within thirty calendar days by paying the fee set in Section 3-43(1) (Section 50-33).

Violations & Fines

Any discharge or illicit connection prohibited by Chapter 50 is enforced through the notice and abatement process of County Code Chapter 41: a warning or Notice of Noncompliance, a correction deadline, and County abatement at the violator's expense if the deadline is missed (Sections 50-27, 50-32, 50-34). Violations are a public nuisance and can also trigger civil or criminal liability under the Clean Water Act and Porter-Cologne Act. Appeals go to the Board within 30 days.

Frequently Asked Questions

What counts as an illegal stormwater discharge in unincorporated Butte County?
Section 50-11 bans any 'illicit discharge': material other than stormwater entering the County storm drain system, natural surface waters, or watercourses. That covers pollutants like fuels, paints, sediment, and wastewater unless the discharge fits one of the narrow exemptions listed in Section 50-12.
Can I wash my car in my driveway?
Yes. Section 50-12(c)(2) exempts individual residential car washing from the discharge prohibition, along with water line flushing, footing drains, air conditioning condensation, and dechlorinated pool water, as long as pollutants in the runoff are controlled.
Do I have to intend to pollute to be in violation?
No. Section 50-16 states a violation occurs irrespective of the discharger's negligence or intent to construct, maintain, or use an illicit connection or cause a prohibited discharge, so an accidental spill can still be cited.
How do I appeal a stormwater notice of violation?
File a written notice of appeal with the Clerk of the Board, along with the appeal fee set in Section 3-43(1), within thirty calendar days of the Administrator's notice, action, or determination, as required by Section 50-33 of the stormwater ordinance.

Sources & Official References

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