AB 1313 California Assembly · 2025-2026 Regular Session

Water quality: permits.

Summary

Under existing law, the State Water Resources Control Board and the 9 California regional water quality control boards regulate water quality and prescribe waste discharge requirements in accordance with the federal national pollutant discharge elimination system (NPDES) permit program established by the federal Clean Water Act and the Porter-Cologne Water Quality Control Act. Existing law requires each regional board to formulate and adopt water quality control plans for all areas within the region, as provided. The bill would require the state board, after making the necessary residual designation authority findings, to establish a statewide commercial, industrial, and institutional NPDES order for properties with 5 acres or more of impervious surface, as provided. The bill would require the state board to publish a draft order of the statewide order for public comment on or before December 31, 2028, or 18 months after the reissuance of a specified statewide permit, as specified. The bill would require the state board to contemporaneously establish rules for offsite compliance agreements to issue with the publication of the draft statewide order for public comment that details the necessary components of an agreement between commercial, industrial, and institutional permittees and local municipalities for achieving offsite stormwater capture and use within the adopted final statewide commercial, industrial, and institutional NPDES order. The bill would require the NPDES order to include multiple compliance options for discharges to select and comply with to be deemed in compliance with applicable water quality based effluent limitations, including, but not limited to, compliance options incentivizing green infrastructure onsite or offsite stormwater capture and use.

Issues: ✓ Environment

Bill status died 1 of 4 stages cleared

Introduction

Feb 2025

Committee Review

Floor Vote

Governor

Introduced Feb 21, 2025 Last action Feb 2, 2026

Maddy AI version diff · 3 comparisons

What changed between versions

05/27/25 - Amended Assembly → AB1313 · 4 edits

MODERATE

The May 27, 2025 amendment to AB 1313 made several substantive changes to how the statewide commercial, industrial, and institutional NPDES order would operate. The most significant change replaced the requirement for the state board to develop a model memorandum of understanding with a requirement to establish rules for offsite compliance agreements, shifting from a voluntary agreement framework to a regulatory rulemaking approach. Additional changes clarified that dischargers (not discharges) select compliance options and added the word 'incentivizing' before green infrastructure options.

REQUIREMENT

Section 2(a)(2): Changed the offsite compliance mechanism from requiring the state board to 'develop a model memorandum of understanding that details the necessary components of an agreement between permittees and local municipalities' to requiring the board to 'establish rules for offsite compliance agreements.' This shifts the approach from a template-based voluntary MOU to a formal rulemaking process, giving the state board more direct regulatory authority over how offsite stormwater capture arrangements work.

Section 2(b): Added the word 'incentivizing' before 'green infrastructure onsite or offsite stormwater capture and use,' making explicit that these compliance options are meant to provide incentives (such as cost offsets or reduced requirements) rather than simply being available alternatives.

DEFINITION

Section 2(b): Changed 'for discharges to select and comply with' to 'for dischargers to select and comply with in order to be deemed in compliance.' This clarifies that it is the entities (dischargers) who choose their compliance pathway, not the discharges themselves, and adds 'in order to' for grammatical precision about the legal effect of selecting a compliance option.

TECHNICAL

The impervious surface threshold was changed from 'five acres or more' (spelled out) to '5 acres or more' (numeral) in the legislative counsel's digest, though the operative statutory text in Section 2(a)(1) retains 'five acres or more.' This is a formatting consistency change rather than a substantive policy change.

03/24/25 - Amended Assembly → 05/27/25 - Amended Assembly · 6 edits · May 27, 2025

MODERATE

The May 27 amendment to AB 1313 removes a nonsubstantive watermaster definition change (Section 22080), adds extensive legislative findings establishing the legal basis for the statewide stormwater order under residual designation authority, shifts the offsite compliance mechanism from a voluntary model MOU to binding rules, and clarifies that dischargers who select and comply with an approved option are deemed in compliance. The fiscal committee vote changed from no to yes, indicating new budgetary implications.

Scope change

The bill's scope narrowed by removing the unrelated watermaster definition amendment, but its legal foundation was strengthened through explicit legislative findings on residual designation authority. The offsite compliance mechanism expanded in force from a voluntary MOU model to binding rules established by the state board.

SCOPE

The amendment to Water Code Section 22080 (a nonsubstantive change to the definition of 'district' for watermaster service purposes) was entirely removed. The bill now focuses solely on adding Section 13383.1.

DEFINITION

A new Section 1 containing legislative findings and declarations (subdivisions a through i) was added, citing EPA data on urban runoff pollution, the legal framework for residual designation authority under federal regulations, and the state's determination that properties with five or more acres of impervious surface contribute to water quality violations.

REQUIREMENT

The state board is now required to make 'residual designation authority findings' specifically, rather than just 'necessary findings,' making the legal predicate for the order explicit and tying it to the federal catch-all provision in 40 CFR 122.26(a)(9)(i).

The state board must now 'establish rules for offsite compliance agreements' rather than 'develop a model memorandum of understanding.' This shifts from a voluntary template approach to a rulemaking process, giving the offsite compliance mechanism greater regulatory force.

ELIGIBILITY

Compliance options language was refined: dischargers may now select and comply with an approved option to be 'deemed in compliance' with applicable water quality based effluent limitations. The term 'green infrastructure' was added as a specific compliance pathway alongside onsite or offsite stormwater capture and use.

FISCAL

The fiscal committee vote changed from 'no' to 'yes,' indicating the bill now carries identifiable state fiscal impact requiring fiscal committee review.

02/21/25 - Introduced → 03/24/25 - Amended Assembly · 6 edits · Mar 24, 2025

MODERATE

The amended version of AB 1313 adds a major new provision requiring the State Water Resources Control Board to establish a statewide NPDES order for commercial, industrial, and institutional stormwater discharges from properties of 5 acres or more. The original bill only made minor definitional changes to watermaster service law; the amendment dramatically expands its scope to include a new water quality permitting framework with a December 31, 2028 deadline for publishing a draft order.

Scope change

The bill expanded from a narrow, nonsubstantive definitional amendment to watermaster service law into a major water quality regulation requiring a new statewide stormwater permitting order for commercial, industrial, and institutional properties of 5 acres or more, with specific compliance flexibility requirements and a model intergovernmental agreement framework.

SCOPE

Adds new Water Code Section 13383.1 requiring the state board to establish a statewide commercial, industrial, and institutional NPDES order regulating stormwater and authorized nonstormwater discharges from facilities with impervious surfaces on properties of 5 acres or more that are significant contributors of pollutants to federally protected surface waters.

TIMELINE

Requires the state board to publish a draft statewide order for public comment on or before December 31, 2028, or 18 months after reissuance of the statewide General Permit for Stormwater Discharges Associated with Industrial Activities (Order 2014-0057-DWQ), whichever is later.

REQUIREMENT

Requires the state board to develop a model memorandum of understanding between commercial, industrial, and institutional permittees and local municipalities for achieving offsite stormwater capture and use, to be issued alongside the draft order for public comment.

Requires the NPDES order to include multiple compliance options with water quality standards, including options that incentivize onsite or offsite stormwater capture and use.

ELIGIBILITY

Prohibits regulated stormwater permittees from being subject to more than one stormwater NPDES order for the same facility. Requires all effluent limitations for industrial stormwater discharges to be incorporated into the statewide order. Excludes construction activity stormwater discharges from this consolidation.

FISCAL

Fiscal committee designation changed from 'no' to 'yes,' indicating the bill now carries fiscal implications due to the new regulatory program.

Floor votes

How they voted

No floor votes recorded yet.

Full legislative history

Actions timeline

Total actions

Key actions

Committee

Amendments

May 27, 2025

Lower · Passed

Read third time and amended. Ordered to third reading. (Page 1744.)

lower

May 23, 2025

Lower · Passed

From committee: Do pass. (Ayes 11. Noes 3.) (May 23).

lower

May 21, 2025

Committee

In committee: Set, first hearing. Referred to APPR. suspense file.

lower

May 14, 2025

Lower · Passed

In committee: Hearing postponed by committee.

lower

Apr 30, 2025

Lower · Passed

From committee: Do pass and re-refer to Com. on APPR. (Ayes 5. Noes 2.) (April 29). Re-referred to Com. on APPR.

lower

Mar 25, 2025

Committee

Re-referred to Com. on E.S & T.M.

lower

Mar 24, 2025

Introduced

From committee chair, with author's amendments: Amend, and re-refer to Com. on E.S & T.M. Read second time and amended.

lower

Mar 24, 2025

Committee

Referred to Com. on E.S & T.M.

lower

Feb 22, 2025

Lower · Passed

From printer. May be heard in committee March 24.

lower

Feb 21, 2025

Introduced

Introduced. To print.

lower

1 primary · 0 co-sponsors