Soil & Compost BMPs and Requirements

Quality landscapes start with healthy soil

Photo of man at construction site
Plan to restore healthy soil on construction sites.

Builders, developers, and landscapers are adopting practices that preserve and improve the soil on building sites to protect our waterways. Local governments including Seattle now require it.

Advantages to builders, consumers, and the environment include: more marketable buildings with healthier landscapes, better erosion control, easier planting, easier long-term maintenance with less water and chemical needs, and reduced stormwater runoff with better water quality for salmon, wildlife, and people too.

Soil best practices during construction:

  • Retain and protect native topsoil & vegetation where practical.
  • Restore disturbed soils, to healthy soil function, by:
    • Stockpiling & reusing good quality site soil, or
    • Tilling 2-3" of compost into site soils, or
    • Bringing in 8" of compost- amended topsoil.
  • Loosen compacted subsoil, if needed, by ripping to 12" depth.
  • Mulch landscape beds after planting.
  • Protect restored soils from erosion or re-compaction by heavy equipment.

Compost requirements for city projects

City of Seattle projects must use compost when it is an appropriate material for that application or project (SMC 20.60.310). Types of projects where the City must plan to use compost include: landscaping, construction and post-construction soil amendments, erosion control, stormwater filtration, and low-impact development.

When purchasing compost, the City, or City contractors, must prioritize purchasing compost products made from City-generated food and yard waste, are certified by a nationally recognized organization, such as the United States Composting Council, and meet quality standards adopted by the WA State Department of Transportation

The following companies are those manufacturing compost, and soil products containing compost, made from City of Seattle-generated food and yard waste.

Lenz Enterprises logo

Lenz Enterprises/GreenBlenz Compost   

Cedar Grove logo

Cedar Grove Compost  

Public Utilities

Andrew Lee, General Manager and CEO
Address: 700 5th Avenue, Suite 4900, Seattle, WA, 98104
Mailing Address: PO Box 34018, Seattle, WA, 98124-5177
Phone: (206) 684-3000
SPUCustomerService@seattle.gov

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Seattle Public Utilities (SPU) is comprised of three major direct-service providing utilities: the Water Utility, the Drainage and Wastewater Utility, and the Solid Waste Utility.