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Chapter 5 — NONRESIDENTIAL MANDATORY MEASURES

Section 5.304 — OUTDOOR WATER USE

2025 California Green Building Standards Code (Title 24, Part 11) · 2025 edition · updated 2026-07-25 · California

5.304.1 Outdoor potable water use in landscape areas. Nonresidential developments shall comply with a local water efficient landscape ordinance or the current California Department of Water Resources’ Model Water Efficient Landscape Ordinance (MWELO), whichever is more stringent.

Notes:

  1. The Model Water Efficient Landscape Ordinance (MWELO) is located in the California Code of Regulations, Title 23, Chapter 2.7, Division 2.

  2. MWELO and supporting documents, including a water budget calculator, are available at: https://www.water.ca.gov/.

5.304.2 Reserved.

5.304.3 Reserved.

5.304.4 Reserved.

5.304.5 Reserved.

5.304.6 Outdoor potable water use in landscape areas. For public schools and community colleges, landscape projects as described in Sections 5.304.6.1 and 5.304.6.2 shall comply with the California Department of Water Resources Model Water Efficient Landscape Ordinance (MWELO) commencing with Section 490 of Chapter 2.7, Division 2, Title 23, California Code of Regulations, except that the evapotranspiration adjustment factor (ETAF) shall be 0.65 with an additional water allowance for special landscape areas (SLA) of 0.35.

Exception: Any project with an aggregate landscape area of 2,500 square feet or less may comply with the prescriptive measures contained in Appendix D of the MWELO.

5.304.6.1 Newly constructed landscapes. New construction projects with an aggregate landscape area equal to or greater than 500 square feet.

5.304.6.2 Rehabilitated landscapes. Rehabilitated landscape projects with an aggregate landscape area equal to or greater than 1,200 square feet.

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Contents — 2025 California Green Building Standards Code (Title 24, Part 11)

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