California Green Building Code (CALGreen) – Irrigation systems

This regulation mandates the use of recycled water in some irrigation systems with the goal of reducing the overall amount of outside water required for irrigation.

CALGreen Code Section A5.305.2: Irrigation systems.

Irrigation systems regulated by a local water efficient landscape ordinance or by the California Department of Water Resources Model Water Efficient Landscape Ordinance (MWELO) shall use recycled water.


The intent of this measure is to reduce the overall outdoor water used for irrigation by requiring specified irrigation systems use recycled water. Requiring irrigation systems subject to the MWELO requirements in Title 23 to use recycled water will help promote water conservation statewide.

Compliance Method:

Provide recycled water for irrigation systems, complying with California Department of Water Resources Model Water Efficient Landscape Ordinance (MWELO) and as acceptable to the local jurisdiction. Provide detail in construction documents for a recycled water system piping plan and specifications for system components.


Plan intake: The plan reviewer should confirm in the construction documents a recycled system piping plan and component specifications. The reviewer should make sure that the required system for irrigation meets applicable local, regional or state standards.

On-site enforcement: The inspector should verify installation of a recycled water system and make sure that the system is installed as shown in the drawings, and using specified components.

(Excerpted from ‘Guide to the 2022 California Green Building Standards Code Nonresidential’ – Appendix A5)

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