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Water Efficient Landscape Ordinance (WELO)

Changes to WELO include:

  • New compost and mulch requirements: At least 4 cubic yards of compost per 1,000 sq. ft. must be incorporated into the soil, unless contraindicated by a soil analysis. At least 3 inches of mulch must be applied to all exposed soil surfaces in planting areas.

  • Lower landscape size threshold: The ordinance applies to new landscape projects of 500 sq. ft. or more (the previous threshold was 2,500 sq. ft.), and to landscape renovation projects of 2,500 sq. ft. or more.

  • Reduced water allowance: The water budget changed from .70 reference evapotranspiration (ET) to .55 reference ET for residential landscapes and .45 reference ET for nonresidential landscapes.

  • New graywater section: The ordinance encourages use of graywater for irrigation.

Landscape professionals: WELO requirements can vary by city. Check with the local jurisdiction's building permits office about specific WELO requirements for your projects.

In 2015, the State of California enacted major changes to the Water Efficient Landscape Ordinance, marking a groundbreaking shift toward landscape design and management practices better suited to the state's climates and conditions.

Here's a list of essential resources for WELO adoption and implementation:

WELO Adoption

The state intends to update WELO every three years. Instead of adopting WELO directly, it may be simpler for local governments to adopt it by reference.

  • Local WELO ordinances - Model Alameda County ordinance from StopWaste and local cities' adopted ordinances

  • State resources - Model WELO language from the Department of Water Resources (DWR) 

WELO Implementation

General Resources

Compost, Mulch & Soil


Professional Expertise

Need more help?

  • If you are local government staff in Alameda County: Contact StopWaste Senior Program Manager Teresa Eade
  • If you are a landscape professional: Check our Training & Events and Resources pages

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