Puget Sound Innovation Stories

Point Defiance Regional Stormwater Treatment Facility

Polluted stormwater is one of the biggest threats to Puget Sound, and the Point Defiance Regional Stormwater Treatment Facility helps counter that threat. Before the facility was built, polluted stormwater from a 754-acre watershed flowed untreated before spilling into an area of the Sound already overloaded with heavy metals from the Tacoma Asarco Smelter Plume, a toxic legacy from a copper smelter that operated for nearly 100 years.

In 2015, Metro Parks Tacoma joined forces with the City of Tacoma to build an innovative water treatment system. At 5,500 square feet, the largest facility of its kind in the world, the facility supports the City of Tacoma’s efforts to meet the requirements of the federal Clean Water Act in an innovative and cost-effective way. Contaminated runoff and floatable materials from streets and properties are trapped before sending runoff down a series of six cascading pools to a series of concrete boxes filled with filtering material and topped with mulch and plants.  The plants were selected specifically to take root in the filter media and thrive on polluted waters.

The facility can handle 8 million gallons of stormwater per day and educators have found it to be a good place to help students learn about innovative ways to address the long-standing problem of water pollution.

Funding Sources:

  • Washington State Department of Ecology
  • City of Tacoma Surface Water Management
  • Metro Parks Tacoma Point Defiance Bond

 Congressional Districts:  6, 10


  • Metro Parks Tacoma
  • City of Tacoma
  • Science and Math Institute
  • Parametrix
  • Site Workshop
  • Local residents

Photo credits: Julie Morse/The Nature Conservancy, Jessie Israel/The Nature Conservancy

Further questions? Think you can use this as inspiration for your own project? Please inquire with:

Jessica Knickerbocker with the City of Tacoma’s Environmental Services


More Info

Publish Date: April 21, 2017
Category: Stormwater
Legislative Districts: Legislative Dist. 28
Counties: Pierce
Habitat Types: Puget Sound
Restoration Focuses: Reduce Pollution | Salmon | Water Quality
Activities: Regulation
Key Benefits:
Funding Sources: