Cal. Water Code - WAT § 10560. Section 10560.
This part shall be known and may be cited as “The Stormwater Resource Planning Act.”
PART 2.3. STORMWATER RESOURCE PLANNING [10560. - 10565.]
Cal. Water Code - WAT 2.3.
in effectCal. Water Code - WAT § 10561. Section 10561.
The Legislature hereby finds and declares all of the following:
(a)
In many parts of the state stormwater and dry weather runoff are underutilized sources of surface water and groundwater supplies. Instead of being viewed as a resource, they are often seen as a problem that must be moved to the ocean as quickly as possible or as a source of contamination, contributing to a loss of usable water supplies and the pollution and impairment of rivers, lakes, streams, and coastal waters.
(b)
Improved management of stormwater and dry weather runoff, including capture, treatment, and reuse by using the natural functions of soils and plants, can improve water quality, reduce localized
flooding, and increase water supplies for beneficial uses and the environment.
(c)
Most of California’s current stormwater drainage systems are designed to capture and convey water away from people and property rather than capturing that water for beneficial uses.
(d)
Historical patterns of precipitation are predicted to change and an increasing amount of California’s water is predicted to fall not as snow in the mountains, but as rain in other areas of the state. This will likely have a profound and transforming effect on California’s hydrologic cycle and much of that water will no longer be captured by California’s reservoirs, many of which are located to capture snow melt.
(e)
When properly designed and managed, the capture and use of stormwater and dry weather
runoff can contribute significantly to local water supplies through onsite storage and use, or letting it infiltrate into the ground to recharge groundwater, either onsite or at regional facilities, thereby increasing available supplies of drinking water.
(f)
New developments and redevelopments should be designed to be consistent with low-impact development principles to improve the retention, use, and infiltration of stormwater and dry weather runoff onsite or at regional facilities.
(g)
Stormwater and dry weather runoff can be managed to achieve environmental and societal benefits such as wetland creation and restoration, riverside habitats, instream flows, and an increase in park and recreation lands, and urban green space.
(h)
Stormwater and dry weather runoff management through multiobjective projects can
achieve additional benefits, including augmenting recreation opportunities for communities, increased tree canopy, reduced urban heat island effect, and improved air quality.
(i)
Proper planning and implementation is vital to ensure that the water supply and other benefits potentially available through better management of stormwater and dry weather runoff do not come at the expense of diminished water quality.
(j)
The capture and use of stormwater and dry weather runoff is not only one of the most cost-effective sources of new water supplies, it is a supply that can often be provided using significantly less energy than other sources of new water supplies.
Cal. Water Code - WAT § 10561.5. Section 10561.5.
Solely for the purposes of this part, and unless the context otherwise requires, the following definitions govern the construction of this part:
(a)
“Dry weather runoff” means surface waterflow and waterflow in storm drains, flood control channels, or other means of runoff conveyance produced by nonstormwater resulting from irrigation, residential, commercial, and industrial activities.
(b)
“Stormwater” means temporary surface water runoff and drainage generated by immediately preceding storms. This definition shall be interpreted consistent with the definition of “stormwater” in Section 122.26 of Title 40 of the Code of Federal
Regulations.
Cal. Water Code - WAT § 10561.7. Section 10561.7.
(a)
A public entity that captures stormwater from urban areas, in accordance with a stormwater resource plan, before the water reaches a natural channel shall be entitled to use the captured water to the extent that the water augments existing water
supplies.
(b)
Nothing in this section shall be construed to do any of the following:
(1)
Alter or impair any existing rights.
(2)
Change existing water rights law.
(3)
Interfere with, amend, or supersede any existing water rights adjudication or other legally mandated water management plan.
(4)
Create a groundwater pumping right where a pumping right does not already
exist.
Cal. Water Code - WAT § 10562. Section 10562.
(a)
One or more public agencies may develop a stormwater resource plan pursuant to this part.
(b)
A stormwater resource plan shall:
(1)
Be developed on a watershed basis.
(2)
Identify and prioritize stormwater and dry weather runoff capture projects for implementation in a quantitative manner, using a metrics-based and integrated evaluation and analysis of multiple benefits to maximize water supply, water quality, flood management, environmental, and other community benefits within the watershed.
(3)
Provide for multiple benefit
project design to maximize water supply, water quality, and environmental and other community benefits.
(4)
Provide for community participation in plan development and implementation.
(5)
Be consistent with, and assist in, compliance with total maximum daily load (TMDL) implementation plans and applicable national pollutant discharge elimination system (NPDES) permits.
(6)
Be consistent with all applicable waste discharge permits.
(7)
Upon development, be submitted to any applicable integrated regional water management group. Upon receipt, the integrated regional water management group shall incorporate the stormwater resource plan into its integrated regional water management plan.
(8)
Prioritize the use of lands or easements in public ownership for stormwater and dry weather runoff projects.
(c)
The proposed or adopted plan shall meet the standards outlined in this section. The plan need not be referred to as a “stormwater resource plan.” Existing planning documents may be utilized as a functionally equivalent plan, including, but not limited to, watershed management plans, integrated resource plans, urban water management plans, or similar plans. If a planning document does not meet the standards of this section, a collection of local and regional plans may constitute a functional equivalent, if the plans collectively meet all of the requirements of this part.
(d)
An entity developing a stormwater resource plan shall identify in the plan all of the following:
(1)
Opportunities to augment local water supply through groundwater recharge or storage for beneficial use of stormwater and dry weather runoff.
(2)
Opportunities for source control for both pollution and stormwater and dry weather runoff volume, onsite and local infiltration, and use of stormwater and dry weather runoff.
(3)
Projects to reestablish natural water drainage treatment and infiltration systems, or mimic natural system functions to the maximum extent feasible.
(4)
Opportunities to develop, restore, or enhance habitat and open space through stormwater and dry weather runoff management, including wetlands, riverside habitats, parkways, and parks.
(5)
Opportunities to use existing
publicly owned lands and easements, including, but not limited to, parks, public open space, community gardens, farm and agricultural preserves, schoolsites, and government office buildings and complexes, to capture, clean, store, and use stormwater and dry weather runoff either onsite or offsite.
(6)
Design criteria and best management practices to prevent stormwater and dry weather runoff pollution and increase effective stormwater and dry weather runoff management for new and upgraded infrastructure and residential, commercial, industrial, and public development. These design criteria and best management practices shall accomplish all of the following:
(A)
Reduce effective impermeability within a watershed by creating permeable surfaces and directing stormwater and dry weather runoff to permeable surfaces, retention basins, cisterns, and other storage for beneficial use.
(B)
Increase water storage for beneficial use through a variety of onsite storage techniques.
(C)
Increase groundwater supplies through infiltration, where appropriate and feasible.
(D)
Support low-impact development for new and upgraded infrastructure and development using low-impact techniques.
(7)
Activities that generate or contribute to the pollution of stormwater or dry weather runoff, or that impair the effective beneficial use of stormwater or dry weather runoff.
(8)
Projects and programs to ensure the effective implementation of the stormwater resource plan pursuant to this part and achieve multiple benefits. These projects and programs shall include the development of appropriate
decision support tools and the data necessary to use the decision support tools.
(9)
Ordinances or other mechanisms necessary to ensure the effective implementation of the stormwater resource plan pursuant to this part.
(e)
A stormwater resource plan shall use measurable factors to identify, quantify, and prioritize potential stormwater and dry weather runoff capture projects.
Cal. Water Code - WAT § 10563. Section 10563.
(a)
This part does not interfere with or prevent the exercise of authority by a public agency to carry out its programs, projects, or responsibilities.
(b)
This part does not affect requirements imposed under any other law.
(c)
(1)
The development of a stormwater resource plan and compliance with this part in accordance with Section 10565 shall be required to receive grants for stormwater and dry weather runoff capture projects from a bond act approved by the voters after January 1, 2014.
(2)
This subdivision does not apply to
either of the following:
(A)
Funds provided for the purpose of developing a stormwater resource plan.
(B)
A grant for a disadvantaged community, as defined in Section 79505.5, with a population of 20,000 or less, and that is not a copermittee for a municipal separate stormwater system national pollutant discharge elimination system (NPDES) permit issued to a municipality with a population greater than 20,000.
Cal. Water Code - WAT § 10564. Section 10564.
For purposes of this part, “low-impact development” means new development or redevelopment projects that employ natural and constructed features that reduce the rate of stormwater runoff, filter out pollutants, facilitate stormwater storage onsite, infiltrate stormwater into the ground to replenish groundwater supplies, or improve the quality of receiving groundwater and surface water.
Cal. Water Code - WAT § 10565. Section 10565.
By July 1, 2016, the board shall establish guidance for this part that shall include, but is not limited to, the following:
(a)
Identifying types of local agencies and nongovernmental organizations that need to be consulted in developing a stormwater resource plan.
(b)
Defining appropriate quantitative methods for identifying and prioritizing opportunities for stormwater and dry weather runoff capture projects.
(c)
Defining the appropriate geographic scale of watersheds for stormwater resource planning.
(d)
Other guidance the board
deems appropriate to achieve the objectives of this part.
Source: CA Legislative Counsel Bulk DataURL: https://downloads.leginfo.legislature.ca.gov/pubinfo_2025.zipFetched: 6/27/2026