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Summary of WELO Changes and Comparison to Bay-Friendly Basics

Route 238 Capital Improvement Project, Hayward - Bay-Friendly Rated in 2015

In 2015, California adopted sweeping changes to the Model Water Efficient Landscape Ordinance (MWELO). Local jurisdictions were required to adopt the model ordinance or more stringent regulations.

Hover over the View Downloads button for PDFs that compare the new MWELO to the 2009 version and to the Bay-Friendly Basics checklist.

What's Changed?

One major change is new requirements for compost and mulch. To improve soil health and and increase water retention, at least four cubic yards of compost per 1,000 sq. ft of area must be incorporated into the soil. At least three inches of mulch must be applied to all exposed soil surfaces in planting areas. 

Other significant changes include:

  • Lower landscape size threshold: The ordinance applies to new landscape projects equal to or greater than 500 sq. ft. (the previous threshold was 2,500 sq. ft.). A prescriptive checklist is available as a compliance option for projects under 2,500 sq. ft. The ordinance also applies to rehabilitated landscape projects equal to or greater than 2,500 sq. ft.
  • 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.
  • Graywater for irrigation: A new section of the ordinance encourages graywater use.
  • Local agency reporting: Local governments must report to Department of Water Resources on their implementation of the ordinance by January 31 of each year.

Return to StopWaste's main WELO page.

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