California Clean Water Act: Permits, Penalties & Citizen Suits

The California Clean Water Act framework is really two overlapping laws: the federal Clean Water Act and the state’s Porter-Cologne Water Quality Control Act. Together they require most dischargers to hold a permit, meet effluent limits, monitor and report, and face administrative penalties up to $10,000 per day or court-imposed penalties up to $25,000 per day when they don’t. The State Water Resources Control Board (SWRCB) and nine Regional Water Quality Control Boards (RWQCBs) run the program, and because Porter-Cologne reaches further than the federal statute, California also regulates discharges to land, to groundwater, and from nonpoint sources like farms.¹

Who Needs a Permit

Discharging pollutants into California waters without authorization is illegal. Two permit families cover almost everything. National Pollutant Discharge Elimination System (NPDES) permits cover discharges to surface waters. Waste Discharge Requirements (WDRs) cover discharges that stay on land or reach groundwater. Which one you need depends on what you release and where it ends up.

Stormwater

Three groups fall under the NPDES stormwater program: municipal storm sewer operators, construction sites, and industrial facilities. Cities and counties of 100,000 or more hold a Phase I permit and must run a full stormwater management program, including street sweeping and storm drain maintenance; smaller municipalities fall under Phase II.²

Any construction project that disturbs one acre or more needs coverage under the Construction General Permit and a Stormwater Pollution Prevention Plan (SWPPP) with erosion and sediment controls.³ Industrial facilities with stormwater exposure fall under the Industrial General Permit (IGP), which requires a SWPPP, routine stormwater sampling, and annual reporting. Exceeding a numeric action level for pollutants such as heavy metals or suspended solids forces an upgrade of controls and more frequent monitoring.

Industrial Wastewater

Process wastewater discharged to surface water needs an individual NPDES permit. The same wastewater discharged to land or groundwater needs WDRs. Effluent limits are built from the beneficial uses and water quality standards of the receiving water body, so food processors, metal finishers, and chemical plants often sit under site-specific limits stricter than general numeric standards.

Agriculture

Agricultural runoff, including irrigation return flows, pesticide residues, and animal waste, is handled as nonpoint source pollution under Porter-Cologne rather than through NPDES. The Irrigated Lands Regulatory Program (ILRP) requires commercial growers to obtain WDRs or conditional waivers depending on region and risk level. Growers have to implement practices to cut nutrient loading, sediment, and pesticide runoff, and they submit annual monitoring reports.

Higher-risk regions carry more. In the Central Valley, the Nitrate Control Program established in 2019 requires growers in designated management zones to work with other operators to monitor groundwater, upgrade facilities, and supply replacement drinking water to affected residents.⁴ If a Regional Board asks a grower for a technical report on water quality impacts, failing to produce it brings penalties of up to $1,000 per day administratively or $5,000 per day in court.

Monitoring and Reporting

Permit holders submit routine monitoring data on a Discharge Monitoring Report (DMR), with pollutant concentrations, flow, and sampling methods. Frequency runs from monthly to annual depending on the permit. Most reporting is electronic: the California Integrated Water Quality System (CIWQS) for general permit data, and the Storm Water Multiple Application and Report Tracking System (SMARTS) for stormwater. The federal E-Reporting Rule requires electronic submission for most NPDES holders.⁵

When something spills or an unauthorized discharge occurs, the clock is short. You must notify the Regional Water Board by telephone within two hours of becoming aware, and call the Office of Emergency Services and the local health department in that same window. A written follow-up documenting location, volume, cause, and corrective actions is due within five business days.⁶ Missing either deadline is itself a citable violation.

What Violations Cost

Enforcement escalates. The lightest step is a Notice of Violation, a formal warning. More serious situations draw a Cleanup and Abatement Order, which compels remediation at the violator’s expense. When harm occurs or violations continue, the boards impose administrative civil liability.

California Water Code Section 13385 sets two tiers:

Administrative penalties imposed by a Regional or State Board: up to $10,000 per day for each day the violation continues, plus up to $10 per gallon for discharge volume not cleaned up above 1,000 gallons.⁷
Court-imposed penalties brought by the Attorney General or a district attorney: up to $25,000 per day per violation, plus up to $25 per gallon above the 1,000-gallon threshold.⁷

Federal penalties stack on top where EPA also has jurisdiction. The federal Clean Water Act’s inflation-adjusted civil cap sits at $68,445 per day per violation for cases assessed after January 2025.⁸ A single discharge event can therefore generate liability under both systems.

Mandatory Minimum Penalties

Some violations carry a mandatory $3,000 minimum per violation that the board cannot waive. A “serious violation” 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. A DMR submitted more than 30 days late also qualifies. So does a chronic pattern: four or more non-serious effluent exceedances in a six-month period.⁷

Supplemental Environmental Projects

A violator who settles can sometimes direct up to 50 percent of the monetary penalty into a Supplemental Environmental Project (SEP), which must provide a benefit beyond anything the violator is already required to do. The redirected amount becomes a suspended liability until the project finishes, typically within 36 months. Regulatory compliance itself can never be traded for a SEP.⁹

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 $15,000, $15,000 plus 50 percent of the remaining liability can be directed to a SEP.⁹

PFAS and Emerging Contaminants

Per- and polyfluoroalkyl substances (PFAS) are moving fast through California’s rulemaking. The state has not finalized enforceable maximum contaminant levels (MCLs) for PFAS in drinking water, but the rulemaking is underway and health-based advisory thresholds apply in the meantime.¹⁰

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, the concentrations 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.¹⁰ EPA finalized federal MCLs for six PFAS compounds in April 2024, with compliance required by 2029. California’s eventual MCLs may run tighter: 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 covering airports, landfills, chrome plating facilities, refineries, bulk fuel terminals, and publicly owned treatment works. Those orders have reached more than 900 facilities and required sampling for up to 40 PFAS compounds.¹¹ Facilities in those categories should expect requirements to tighten as analytical methods and the state framework mature.

Challenging a Regional Board Decision

If a Regional Board issues a permit, sets a condition, or imposes a penalty you believe is improper, California Water Code Section 13320 lets you petition the State Water Board for review. The window is tight: 30 days from the Regional Board’s action.¹² If the Regional Board failed to act on a request, the 30 days starts when the board formally refuses or 60 days after your request, whichever comes first.

The petition must be written. It needs to identify the action challenged, explain why it was improper, show how you are affected, state the relief you want, cite your legal authorities, and confirm you raised the issues before the Regional Board (or explain why you couldn’t).¹³

Here’s the trap. Filing a petition does not pause compliance. An administrative civil liability payment is suspended during State Board review, but for every other kind of order, including permit conditions and cleanup requirements, you must separately request a stay and have it granted. If you include a stay request with your petition, the State Board must act on it within 60 days of accepting the petition.¹² Assuming an appeal freezes everything can rack up additional violations while you wait.

Citizen Suits

When agencies don’t act, private citizens and environmental groups can. The federal Clean Water Act’s citizen suit provision lets anyone sue a polluter for ongoing violations of discharge permits or effluent standards. Before filing, the plaintiff must give written notice to the alleged violator, EPA, and the state, then wait 60 days.¹⁴ If a regulatory agency opens its own enforcement action during that window, the citizen suit is generally preempted.

Citizen suits can seek injunctive relief forcing the violator to stop polluting and install controls, plus civil penalties paid to the U.S. Treasury. Successful plaintiffs can recover attorney’s fees, which keeps these cases financially viable for environmental organizations. Public participation also happens upstream of litigation: Regional Boards hold public hearings before approving permits or taking major enforcement actions, and residents can submit written comments or testify on proposed permit conditions. Whistleblower protections under state and federal law shield employees who report violations.

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