Water Quality and Supply Issues Monthly Update - May 2026
May is in full swing, and things are heating up across the construction and water quality landscape. ☀️ From major regulatory developments to new legislative proposals and upcoming industry events, there is no shortage of important activity shaping our industry this month.
At CICWQ, we remain committed to keeping our members informed, prepared, and engaged as new policies and permitting requirements continue to evolve throughout the state. Our goal is to break down complex issues into practical insights that help you stay ahead and protect your projects, businesses, and communities.
Here’s what you need to know this month:
💧 Santa Ana MS4 Permit Update
After years of development, legal challenges, and stakeholder debate, the Santa Ana Regional Water Quality Control Board has released its final Tentative Order for the Regional MS4 Permit, which affects three Southern California counties.
⚖️ Legislative Alert: AB 2322 & SB 601
Two California bills could introduce additional water quality permitting requirements for businesses and development projects statewide, creating new compliance concerns for the regulated community.
🎓 Summer 2026 Water Policy Events & Education Opportunities
CICWQ members continue to lead the conversation on water policy through educational seminars and professional development events happening this summer across Northern and Southern California.
👇 We encourage you to explore each update below, stay informed on emerging regulatory changes, and take advantage of opportunities to engage with industry experts and fellow professionals throughout California.
MAY NEWSWORTHY ITEMS
1️⃣ Final Tentative Order for a Regional Municipal Separate Storm Sewer System (MS4) Permit Released by the Santa Ana Regional Water Quality Control Board
During the first week of May, the Santa Ana Regional Water Quality Control Board released the Tentative Order for the Santa Ana Watershed Regional MS4 Permit, covering portions of Orange, Riverside, and San Bernardino counties. A 45-day comment period has been established, ending on June 19, 2026, and an adoption hearing has been proposed to commence on July 24, 2026, in the City of Orange.
The Regional MS4 permit is the first of its kind for the Santa Ana River Watershed, consolidating three separate permits originally issued to individual counties in the early 1990s and renewed separately thereafter, until now. CICWQ, and especially its Building Industry Association members representing the housing industry, have been involved at every step of the way in permit development, as the compliance requirements of the proposed Regional MS4 permit impact nearly every housing project to be built in the 3-County area. CICWQ has worked closely and tirelessly with the principal permittees from the 3-County area to align on concerns and fight for flexibility and the use of multiple compliance pathways to allow much-needed housing to be built, especially as housing is directed more and more into existing urban areas, where managing stormwater runoff is complex and costly.
Next month, we will summarize for our readers the major concerns with the proposed Regional MS4 permit and offer suggested improvements, all aimed at building more housing in Southern California while protecting and improving water quality. Review the redline version of the proposed Regional permit, known as a Tentative Order, issued by the Regional Board on May 5.
2️⃣ 2026 California Legislative Session Bill Alert: Oppose and Stop AB 2322 (Papan)
Efforts to further regulate stormwater runoff leaving public and private properties in California will just not stop. For many months, we’ve alerted our readers to proposed legislation, AB 1313 (Papan), that would have imposed sweeping, new, and costly stormwater runoff and treatment controls for commercial, industrial, and institutional properties across California. Fortunately, AB 1313 died earlier in 2026, as it did not obtain enough votes to move out of the Assembly. However, a spin-off, so-called “spot bill” AB 2322, was just introduced by Assembly member Papan.
AB 2322 (Papan) is a stripped-down version of AB 1313, and proposes to create a single, uniform, statewide definition of commercial, industrial, and institutional sites, for the purpose of adding an additional and costly layer of permitting beyond existing municipal separate storm sewer system permits and existing industrial and construction general permits. California Coastkeeper, the bill’s primary supporter, just won’t quit this effort to add a new permit regime, and our industry needs to do everything possible to stop AB 2322 (Papan) from advancing.
And, as we’ve alerted our readers before in 2025 and 2026, SB 601 (Allen) is still alive in the Senate and may still have a chance to move forward, although our advocates tell us it’s languishing in committee. SB 601 is simply a terrible bill that proposes to rewrite California water law and, most egregiously, would try to change the definition of a water of the state. Keep pushing your legislative advocates to oppose this bill.
3️⃣ Water Policy Educational and Professional Development Events in Northern and Southern California Summer 2026
Southern California Water Conference
Building A Reliable Water Future Together
August 14, 2026
Come celebrate the 20th Anniversary of the Southern California Water Conference, presented and hosted by the Building Industry Association of Southern California. The annual Water Conference features water industry experts from California and neighboring states who share valuable, timely information on a range of critical topics to secure a reliable, sustainable water future. This year’s conference features several topical areas, including an hour-long panel titled "Building the Next 50-year Water Portfolio: What the Housing Industry Needs from California Water Policy."
California Water Policy Conference
Adapting Together: Water Policy for a Changing California
September 29, 2026
For more than three decades, the California Water Policy Conference has been a trusted forum for advancing dialogue on the state’s most pressing water challenges. This year's event will bring together top leaders from urban and agricultural water agencies, state government, environmental organizations, academia, and the private sector to examine the policies shaping California’s water future.
