AB 638 requires the State Water Resources Control Board to develop, by December 1, 2026, nonbinding recommendations for capturing and using stormwater to irrigate ‘‘urban public lands.’’ The recommendations must identify opportunities to offset potable water use while posing ‘‘minimal to no’’ public health risk and must include suggested pathogen and pathogen‑indicator approaches, total suspended solids (TSS), toxics monitoring, and both structural and nonstructural best management practices (BMPs). The bill also mandates written public comment on the draft recommendations and approval only after a public hearing.
This is guidance-level intervention rather than a regulatory standard. Its primary effect will be to give municipalities, stormwater agencies, parks departments, and permittees a baseline for designing nonpotable reuse projects for public landscapes.
It also creates a near-term deliverable that will shape planning, monitoring, and capital decisions—without directly imposing numeric limits, funding, or binding permit conditions.
At a Glance
What It Does
The bill directs the State Water Resources Control Board to draft and approve recommendations for capturing stormwater and using it to irrigate specified urban public lands, focusing on measures that reduce potable water use while minimizing public health risk. The recommendations must cover pathogen/pathogen indicators, TSS, toxics, and structural and nonstructural BMPs, and the Board must solicit written comment and hold a public hearing before final approval.
Who It Affects
City and county parks departments, municipal stormwater permittees and regional stormwater agencies, public golf course operators, water districts that supply potable water, and consultants/engineers who design reuse systems will be the primary audiences for the guidance. State Water Board staff bear the production and outreach burden.
Why It Matters
Although nonbinding, the guidance will influence design standards, monitoring programs, and local capital planning for nonpotable reuse projects. It creates an explicit, statewide signal that captured stormwater is a contemplated source for irrigating public landscapes—potentially lowering potable demand but also triggering new monitoring and maintenance expectations.
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What This Bill Actually Does
AB 638 asks the State Water Resources Control Board to produce practical recommendations for using captured stormwater to water ‘‘urban public lands.’’ The statute sets a firm deadline—December 1, 2026—and limits the Board’s charge to developing guidance rather than promulgating enforceable regulations. The guidance must weigh how captured stormwater can offset potable irrigation while presenting minimal to no public health risk.
The bill specifies topics the recommendations must address: identifying opportunities to offset potable demand, suggesting how to handle pathogens and pathogen indicators, considering total suspended solids and toxics, and listing both structural (for example, retention or treatment systems) and nonstructural (for example, operation and maintenance, source controls) BMPs. That scope pushes the Board to consider water quality, treatment, and operational practices together rather than in isolation.Before finalizing its recommendations, the Board must solicit written public comment and hold a public hearing; only after that hearing may it approve the final package.
The statute also defines ‘‘urban public lands’’ broadly to include state, city, or county‑owned land or land dedicated for public access, with examples such as parks, street medians, parkways, and golf courses. Taken together, the bill provides a short, concrete timetable for producing unified guidance that local implementers can use when planning nonpotable irrigation projects for public landscapes.
The Five Things You Need to Know
The State Water Resources Control Board must develop recommendations by December 1, 2026, specifically aimed at using captured stormwater to irrigate urban public lands.
The recommendations must identify opportunities to offset potable water demand while posing ‘‘minimal to no’’ public health risks.
The Board must include guidance on pathogens and pathogen indicators, total suspended solids (TSS), toxics, and structural and nonstructural best management practices.
The Board must solicit and receive written public comments on the draft recommendations and may only approve final recommendations after completing a public hearing.
The statute defines ‘‘urban public lands’’ to include state, city, or county‑owned land or land dedicated for public access, explicitly citing parks, street medians, parkways, and golf courses as examples.
Section-by-Section Breakdown
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Directive and deadline to develop guidance
This subsection creates the Board’s core task: develop recommendations for stormwater capture and irrigation of urban public lands by December 1, 2026. Mechanically, it is a time‑bound, project‑level directive rather than an authorization for rulemaking. Practically, the Board must scope and staff a deliverable that synthesizes technical and public‑health considerations into usable guidance for practitioners.
Offset potable demand while protecting health
This paragraph requires the Board to evaluate and present opportunities where captured stormwater can replace potable supply for irrigation, with the explicit objective of ‘‘minimal to no’’ public health risk. The wording forces the Board to balance conservatism in health protection with the practical goal of conserving potable water, which will affect recommended treatment levels, acceptable uses, and deployment priorities across different types of public landscapes.
Technical components: pathogens, TSS, toxics, and BMPs
The Board must offer recommendations on pathogen metrics and indicators, TSS, toxics, and both structural and nonstructural BMPs. That structure directs attention to monitoring indicators and treatment practices rather than prescribing single numeric standards; however, the inclusion of specific categories signals the Board should propose measurable approaches (choice of indicator organisms, TSS targets, toxics screening priorities, and examples of BMPs) that local implementers can adopt or adapt.
Public engagement requirement before approval
The Board must solicit written public comment on the proposed recommendations and may only approve the final recommendations after a public hearing. This sequencing gives stakeholders a formal opportunity to shape technical choices and creates a transparent record for any subsequent local adoption—developers, municipalities, and public‑health advocates will have to weigh in during the draft stage.
Definition of urban public lands
The statute defines the intended scope of application: urban lands owned by the state, a city, or county, or lands dedicated for public access, and it lists examples including parks, street medians and parkways, and golf courses. The definition is broad and practical, but it could leave edge cases (e.g., privately owned lands with public access easements) to interpretation when implementers apply the guidance.
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Explore Environment in Codify Search →Who Benefits and Who Bears the Cost
Every bill creates winners and losers. Here's who stands to gain and who bears the cost.
Who Benefits
- Municipal parks and public‑land managers — The guidance gives operational options to reduce potable irrigation costs and sustain urban green space during droughts by identifying acceptable reuse practices and BMPs.
- Regional stormwater agencies and municipal permittees — A single, statewide set of recommendations reduces technical uncertainty when designing capture and reuse projects and supports grant and capital program planning.
- Landscape architects and engineering firms — Clear technical guidance creates market demand for designs and systems tailored to nonpotable stormwater reuse on public lands.
- Communities in water‑stressed urban areas — Expanded nonpotable irrigation options may preserve parks and urban canopy without drawing on limited potable supplies.
Who Bears the Cost
- State Water Resources Control Board — Producing technically credible recommendations, conducting outreach, and convening hearings will consume staff time and technical resources.
- Local government implementers (parks departments, water districts, stormwater permittees) — Implementing the guidance likely requires investments in treatment infrastructure, monitoring programs, maintenance, and operations.
- Municipal budgets and taxpayers — Retrofitting irrigation systems, adding monitoring, and regular maintenance impose capital and ongoing costs that local governments must fund absent new state appropriations.
- Small contractors and maintenance teams — New BMP and monitoring requirements will change specifications and may increase project complexity and cost for vendors that serve public‑land clients.
Key Issues
The Core Tension
The bill’s central dilemma is balancing public‑health protection against the practical goal of conserving potable water—tighter, more conservative pathogen and toxics recommendations protect health but raise costs and slow adoption; looser guidance speeds water savings but increases uncertainty about health outcomes and public acceptance.
The bill asks for guidance, not regulation. That keeps the Board’s products flexible and politically easier to deliver, but it also means jurisdictions can choose whether to adopt the recommendations—leading to uneven implementation across California.
The statute lists technical categories (pathogens, TSS, toxics, BMPs) but does not define acceptable indicator organisms, numeric targets, or monitoring frequency. Those technical choices will determine both public‑health protection and project cost; the Board’s drafting choices will therefore have real consequences even if the recommendations remain nonbinding.
A central implementation challenge is funding and capacity. Municipalities and parks agencies will need capital for treatment or storage and recurring budgets for monitoring and maintenance, yet AB 638 contains no appropriation.
The requirement to aim for ‘‘minimal to no’’ public health risk creates ambiguity: it invites a precautionary approach that raises costs and may slow project rollout, or a more permissive approach that reduces costs but risks public concern. Finally, the definition of ‘‘urban public lands’’ is functional but broad; questions will arise about privately owned facilities with public access, mixed‑use parcels, and who takes legal responsibility for monitoring and public‑health outcomes under varied ownership arrangements.
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