California Clean Water Act: Permits, Reporting, and Penalties

The California Clean Water Act framework is not a single statute but a pairing: the federal Clean Water Act plus the state’s Porter-Cologne Water Quality Control Act, administered together by the State Water Resources Control Board (SWRCB) and nine Regional Water Quality Control Boards (RWQCBs). That pairing regulates discharges to surface water, groundwater, and land through a permit system, and it backs the rules with administrative penalties of up to $10,000 per day and court-imposed penalties of up to $25,000 per day.¹ If you run an industrial facility, farm, construction site, or municipal system, the state’s rules almost certainly reach you, and often reach further than the federal rules alone.

Who Regulates Water Pollution in California

Porter-Cologne gives the SWRCB and the nine Regional Boards authority to set water quality standards, issue permits, and pursue enforcement for pollution of any waters of the state, including groundwater.² The federal Clean Water Act largely stops at point sources: identifiable pipes and outfalls discharging to surface waters. California picks up where the federal law leaves off, reaching nonpoint sources such as agricultural runoff and urban stormwater under its own statutory authority.

Each Regional Board writes a Basin Plan defining the beneficial uses of water bodies in its region and setting the numeric and narrative objectives that protect those uses. Basin Plans track federal minimums but frequently go stricter, especially for drinking water sources and sensitive ecosystems.

Overlaying all of it is the state’s Antidegradation Policy, adopted in 1968 as Resolution 68-16. High-quality waters must be maintained unless a proposed change benefits the public, does not harm current or anticipated uses, and does not drop quality below established standards.³ The practical effect: any degradation of clean water triggers a justification requirement, and dischargers often end up with tighter limits than federal law would produce on its own.

Which Permit You Need

Discharging pollutants into California waters without a permit is illegal. Two main permit types cover almost everything: National Pollutant Discharge Elimination System (NPDES) permits for discharges to surface waters, and Waste Discharge Requirements (WDRs) for discharges that stay on land or reach groundwater. Which one applies depends on what you’re discharging and where it goes.

Stormwater

NPDES stormwater rules cover three groups: municipal storm sewer systems, construction sites, and industrial facilities. Phase I applies to municipalities with populations of 100,000 or more and requires comprehensive stormwater management programs including street sweeping and storm drain maintenance.⁴ Phase II covers smaller municipalities with less extensive requirements.

Any construction project disturbing one or more acres must get coverage under the Construction General Permit and develop a Stormwater Pollution Prevention Plan (SWPPP) with erosion controls and sediment barriers.⁵ Industrial facilities with stormwater exposure fall under the Industrial General Permit, which requires a SWPPP, periodic stormwater sampling, and annual reporting. Sample results above numeric action levels for pollutants such as heavy metals or suspended solids trigger required upgrades to pollution controls and increased monitoring.

Industrial Wastewater

Facilities that discharge process wastewater to surface waters need an individual NPDES permit; those discharging to land or groundwater need WDRs. Effluent limits are set from the water quality standards and beneficial uses of the receiving water. Food processing, metal finishing, and chemical manufacturing typically see site-specific limits stricter than general standards because of what they discharge.

Agricultural Discharges

Irrigation return flows, pesticide residues, and animal waste are treated as nonpoint source pollution under Porter-Cologne rather than through federal NPDES. The Irrigated Lands Regulatory Program (ILRP) requires commercial farms to hold WDRs or conditional waivers, with the specifics varying by region and risk level. Growers must implement practices that reduce nutrient loading, sediment runoff, and pesticide contamination, and they must file annual water quality monitoring reports.

The Central Valley and Central Coast face stricter requirements because of chronic nitrate contamination in groundwater. Under the Central Valley Water Board’s Nitrate Control Program, established in 2019, growers in designated management zones must work together to monitor groundwater, upgrade facilities, and provide replacement drinking water to affected residents.⁶ Failing to submit a technical report demanded by the Regional Board can bring penalties of up to $1,000 per day administratively, or up to $5,000 per day if the matter goes to court.

Reporting: Routine and Emergency

Permit holders submit monitoring data through Discharge Monitoring Reports (DMRs). The reporting frequency depends on the permit, from monthly to annually. Most submissions go through electronic systems: the California Integrated Water Quality System (CIWQS) for general permit data, the Storm Water Multiple Application and Report Tracking System (SMARTS) for stormwater. The federal E-Reporting Rule requires electronic submission for most NPDES permit holders.⁷

Spills and unauthorized discharges compress the schedule sharply. You must notify the Regional Water Board by telephone within two hours of becoming aware of the event, and reach the Office of Emergency Services and the local health department in the same window. A written report covering location, volume, cause, and corrective actions is due within five business days.⁸ Missing either deadline is itself a separately citable violation.

Penalties

Enforcement escalates in steps. A Notice of Violation is the mildest, essentially a formal warning. Cleanup and Abatement Orders compel remediation at the violator’s expense. When harm is real or violations persist, the boards impose administrative civil liability, and the Attorney General or a district attorney can take the case to court.

California Water Code Section 13385 sets two tiers of civil liability:

Administrative penalties, imposed by a Regional or State Board, run up to $10,000 per day for each day a violation continues, plus up to $10 per gallon for any unrecovered discharge volume above 1,000 gallons.¹
Court-imposed penalties run up to $25,000 per day per violation, plus up to $25 per gallon for unrecovered discharge volume above 1,000 gallons.¹

Federal penalties apply on top when both jurisdictions reach the same discharge. The federal Clean Water Act’s inflation-adjusted civil penalty cap is $68,445 per day per violation for cases assessed after January 2025.⁹ A single discharge event can produce liability under both systems.

Mandatory Minimums

Some violations carry a $3,000 mandatory minimum penalty per violation that the Regional Board cannot waive. A “serious violation” here means a discharge exceeding effluent limits for a Group II pollutant by 20 percent or more, or a Group I pollutant by 40 percent or more. Failing to submit a required DMR more than 30 days past the deadline also counts as a serious violation. Chronic violations, defined as four or more non-serious effluent exceedances in a six-month period, likewise trigger the $3,000 minimum per violation.¹

Redirecting Penalties Into Local Projects

Violators who settle can sometimes redirect up to 50 percent of a monetary penalty into a Supplemental Environmental Project (SEP), which must produce an environmental benefit above and beyond what the violator is already required to do. The redirected amount becomes a suspended liability until the project is completed, typically within 36 months.¹⁰

The 50 percent limit can be exceeded when the SEP benefits a disadvantaged community, an environmental justice community, or furthers the human right to water. For mandatory minimum penalties of $15,000 or less, the entire amount can go to a SEP without special approval. Above that, $15,000 plus 50 percent of the remaining liability can be directed to a SEP.¹⁰ The boards cannot trade away regulatory compliance itself in exchange for a SEP.

PFAS and Emerging Contaminants

Per- and polyfluoroalkyl substances are one of the most active regulatory frontiers in California. The state has not yet finalized enforceable maximum contaminant levels for PFAS in drinking water, but rulemaking is underway. As of October 2025, the Division of Drinking Water set notification levels at 4.0 nanograms per liter (ng/L) for both PFOA and PFOS. Response levels, at which water systems should consider removing a source from service or installing treatment, are 10 ng/L for PFOA and 40 ng/L for PFOS.¹¹

EPA finalized MCLs for six PFAS compounds in April 2024, with compliance required by 2029. California’s eventual MCLs may run stricter, given that the state’s public health goals for PFOA (0.007 ng/L) and PFOS (1 ng/L) sit far below federal limits.

On the discharge side, the SWRCB has issued investigative orders requiring PFAS sampling at airports, landfills, chrome plating facilities, refineries, bulk fuel terminals, and publicly owned treatment works. Those orders have reached more than 900 facilities and covered up to 40 PFAS compounds.¹² If your facility fits one of those categories, expect monitoring requirements to tighten as the framework matures.

Appealing a Regional Board Decision

If you think a Regional Board acted improperly on a permit, permit condition, or penalty, you can petition the SWRCB for review under Water Code Section 13320. The window is short: your petition must be received within 30 days of the Regional Board’s action.¹³ If the Regional Board failed to act on a request you made, the 30-day clock starts when the board formally refuses or 60 days after your request, whichever comes first.

The petition must be in writing and identify the specific action being challenged, why it was improper, how you’re affected, and the relief you want. Include a statement of legal authorities and proof that you raised these issues before the Regional Board, or an explanation of why you couldn’t.¹⁴

A petition does not automatically pause compliance obligations. If it involves an administrative civil liability assessment, payment is suspended during State Board review. For everything else, including permit conditions and cleanup requirements, you must separately request a stay and have it granted before you can stop complying. If your petition includes a stay request, the State Board must act on the stay within 60 days of accepting the petition.¹³ Assuming an appeal freezes the whole order can produce additional violations while you wait.

Citizen Suits

Regulators are not the only enforcers. The federal Clean Water Act’s citizen suit provision lets any person sue a polluter for ongoing violations of discharge permits or effluent standards. Before filing, the plaintiff must send written notice to the alleged violator, EPA, and the state, then wait 60 days.¹⁵ If a regulatory agency files its own action during that window, the citizen suit is generally preempted.

Citizen suits can seek injunctions and civil penalties, with penalties payable to the U.S. Treasury. Successful plaintiffs can recover attorney’s fees, which keeps these cases financially viable for environmental organizations. Public participation happens earlier in the process too: Regional Boards hold public hearings before approving permits or major enforcement actions, and residents can submit written comments or testify on proposed conditions. State and federal whistleblower protections cover employees who report violations.

1
California Legislative Information. California Water Code WAT 13385
2
California Regional Water Quality Control Boards. Enforcement – Los Angeles Regional Water Quality Control Board
3
California State Water Resources Control Board. Statement of Policy with Respect to Maintaining High Quality of Waters in California (Antidegradation Policy)
4
US EPA. Stormwater Discharges from Municipal Sources
5
US EPA. Construction General Permit (CGP) Frequent Questions
6
Central Valley Regional Water Quality Control Board. Notice of Intent Guidance for the Nitrate Control Program Individual Permitting Approach (Path A)
7
eCFR. 40 CFR Part 127 – NPDES Electronic Reporting
8
California State Water Resources Control Board. Spill Reporting Procedures – Mandatory Procedures and Requirements for Addressing Spills and Other Unauthorized Discharges
9
eCFR. 40 CFR 19.4 – Statutory Civil Monetary Penalties, as Adjusted for Inflation
10
State Water Resources Control Board. Policy on Supplemental Environmental Projects
11
California State Water Resources Control Board. PFAS – Per- and Polyfluoroalkyl Substances Drinking Water Systems
12
California State Water Resources Control Board. CA PFAS Timeline
13
California State Water Resources Control Board. California Water Code 13320
14
State Water Resources Control Board. Water Quality Petitions – Instructions for Filing
15
Office of the Law Revision Counsel. 33 USC 1365 – Citizen Suits