The 120-Day WDR Rule in California, Explained for Developers

Where does the 120-day figure come from?

From regional board guidance on when to file. The North Coast Regional Water Board's Form 200 application Q&A says the first step to obtain WDRs is to file the Report of Waste Discharge form (Form 200), with the necessary supplemental information, at least 120 days before beginning to discharge waste.

The Colorado River Basin Water Board's WDR guidance page gives the same step. Both say developing and adopting WDRs normally takes about three months: a typical case, not a deadline.

Other boards use the number differently. The San Diego Water Board's guidance on preparing a Report of Waste Discharge for discharges to land (November 2018) says staff do a preliminary completeness review within 30 days of receipt. Once the report is complete, staff process it in accordance with state regulations within 120 days.

So the same figure can mean a filing lead time or a processing window, depending on the board. Ask yours which it means, and get the answer in writing.

What does the Water Code actually require?

A report before any new discharge, then WDRs, a waiver or a conditional 140-day wait.

Water Code §13260 requires anyone discharging or proposing to discharge waste that could affect the quality of the waters of the state, other than into a community sewer system, to file a report with the regional board. A material change in the character, location or volume of a discharge needs a new report.

Under Water Code §13264, no one may start a new discharge, or materially change one, before filing that report. After filing, the discharge still waits for the first of three events:

• the regional board issues WDRs under §13263;
• 140 days pass after compliance with §13260, if the waste does not create or threaten pollution or nuisance and a CEQA condition is met;
• the board waives WDRs under §13269.

The CEQA condition is met when the project is not subject to CEQA, or when a set time has passed in the CEQA process: from 90 days to one year, depending on the board's role and the environmental document.

The 140 days is not an approval. Section 13260 calls for a report containing the information the regional board requires, so a thin report is a weak start for any clock. Treat the 140-day path as a question for counsel and the board, not a schedule date.

What happens between filing and adoption?

A completeness review, a draft, public comment and a hearing. The North Coast Q&A describes the steps after filing:

1. Board staff review the report for completeness and may ask for more information.
2. Once it is complete, staff decide whether the board should adopt WDRs, prohibit the discharge or waive WDRs.
3. Proposed WDRs go to interested persons and agencies for at least 30 days of comment, and staff may revise them.
4. The board holds a public hearing, noticed at least 30 days ahead, and may adopt the WDRs as proposed or modified.

Each request for more information is a round trip that no filing date accounts for.

Why do technical gaps cost more time than the filing date?

Because staff write your WDRs from the report. The San Diego guidance says it must give staff enough technical information to develop a tentative order with draft WDRs.

Its list of what that can include, one board's example, starts with a technical report stamped by a California professional engineer covering:

• waste characterization, including average and peak daily flow and seasonal variation;
• the treatment process and how it reaches the needed effluent quality;
• any nutrient or salinity management measures;
• the disposal site, with long-term application quantities, seasonal conditions, soil profile, and groundwater depth, flow and quality;
• storage for periods when effluent cannot be disposed of;
• how the discharge interacts with groundwater, with a monitoring proposal where needed.

It also asks for a topographic map showing wells within one mile, and the CEQA documents. Where no other disposal is available, it asks for storage that holds 84 days of effluent, unless water balance calculations show a smaller volume is adequate.

A thin water balance, an undefined disposal area or groundwater data from another site invites the questions that add review rounds. Boards differ, so ask yours for its own list before you start.

Is there a shorter path for a small project?

Sometimes, through a general order or a waiver.

The State Water Board's general order for small domestic wastewater systems, Order WQ 2014-0153-DWQ, covers systems with a monthly average flow of 100,000 gallons per day or less that discharge to land. Coverage starts with a Report of Waste Discharge to the regional board.

Under Water Code §13269, a board can instead waive WDRs for a specific discharge or type of discharge, if the waiver fits the water quality control plan and the public interest. A waiver is conditional, can be ended at any time and lasts no more than five years, though it can be renewed.

If the treated water will be reused, the recycled water rules and a Title 22 engineering report come into play. Our guide to choosing between WDRs and recycled water rules covers that decision, and our California wastewater engineering page summarizes the other permit paths.

How should a developer schedule around WDRs?

Tie the discharge start, and the construction milestones that depend on it, to adopted WDRs, not to the filing date. Show the filing, the completeness review, a contingency for comment rounds and the hearing as separate lines.

Your WDR schedule is ready to show a lender only if all six answers are yes. Any no means fix that line first.

1. The regional board has confirmed which path applies: individual WDRs, a general order or a waiver.
2. You know, in writing, what your board's 120-day figure means.
3. Your CEQA lead agency, document type and status are known.
4. The technical report follows the board's list, with a site water balance, a defined disposal area and site groundwater data.
5. A monitoring proposal is drafted.
6. The schedule starts discharge at adopted WDRs, general order coverage or a waiver, with contingency for at least one information request.

Questions for your engineer and the board before you file:

• Which staff unit will review this discharge?
• Does a general order fit, and what would rule it out?
• What does your board consider a complete report?
• When are the board's hearings, and how far ahead are agendas set?

This article is general education from the Water Code and regional board guidance as of October 2026. Boards differ, it is not legal advice, and no source here promises an approval date.

Frequently asked questions

Does the 120-day WDR rule mean my WDRs will be adopted within 120 days?

No. In regional board guidance, 120 days is how far ahead to file before discharging, or, in San Diego's guidance, the processing window after a complete report. Individual WDRs still need a completeness review, a comment period and a hearing.

Can I start discharging 140 days after filing if the board has not acted?

Only in the narrow case Water Code §13264 describes, with every condition met. Treat it as a question for counsel and the board, never a schedule assumption.

What is the difference between WDRs and an NPDES permit?

Where the waste goes. Board guidance sends a discharge to land or groundwater down the WDR path, filed on Form 200. A discharge of pollutants to surface water needs an NPDES permit, filed on federal forms along with Form 200.

I'm developing a California subdivision with its own small treatment plant and spray fields. How early should we talk to the regional board?

Before you fill out Form 200. The North Coast Q&A highly recommends contacting board staff first, and its guidance asks for the report at least 120 days before discharge begins. Early contact can also tell you whether the small-system general order fits.

My lender wants an approval date for our California WDRs in the construction schedule. What date can I honestly give them?

A target, not a promise. Give the filing date, the completeness review, a contingency for information requests and comments, and the hearing date the board expects. Nothing cited here guarantees adoption by a fixed date.

Related resources

• The Six Month Rule: What California’s NPDES Timeline Actually Says and What It Does Not
• The 90-Day Rule: What California Industrial Users Must Do Before Discharging to a Sewer
• Local Sewer Connection vs. State Permit: When a California SIU Permit Is the Faster Path
• The Title 22 Engineering Report: The Real Bottleneck in California Recycled Water Projects

Building a WDR schedule for a California project?

MES, with an office in San Jose, California, helps developers choose the disposal path, prepare the technical work behind a Report of Waste Discharge, and build a schedule that shows each review step.

We specialize in:

• Wastewater disposal path assessments
• Report of Waste Discharge technical reports
• Water balance and disposal area design
• Wastewater treatment system design
• Title 22 engineering reports
• Groundwater monitoring plans

Modern Engineering Solutions, McKinney, Texas. Contact: (214) 833-6748 or mod-eng.com