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The Salmon Creek Wastewater Treatment Plant serves an estimated 100,000 Clark County residents living inside the Clark Regional Wastewater District and the cities of Battle Ground and Ridgefield.
The plant's capacity is 15 million gallons a day, considerably more than its typical daily flow of 8 million to 10 million gallons.
Public Works operates and maintains the plant, along with its pump stations and regional interceptor sewer lines. The department’s goal is to operate the system in a safe, dependable and cost-effective manner that meets all environmental regulations.
More information on how the plant works is available on the Discovery Clean Water Alliance's website.
Environmental protection
The Washington State Department of Ecology recognized the plant for 100 percent compliance with laws and regulations to protect the environment in 2020.
The award marks the 14th year in a row the Salmon Creek plant has received an Outstanding Performance Award from the state.
“It’s not easy to operate a wastewater treatment plant 24 hours a day, 365 days a year, without violations,” Vincent McGowan, Ecology’s Water Quality Program Manager, wrote in a July 23 letter.
“Your excellent record is a credit to the dedicated operators who are responsible for running this award-winning plant.”
Do not flush wipes, other products
Residents should never use their toilets to dispose of wipes and other consumer products, including those packaged as "flushable."
Even if these products do not obstruct your home's sewer lines, they can clog pump stations that convey wastewater to the Salmon Creek plant.
The only items that should be flushed down your toilet are human waste and tissue. More information is available on the What Not to Flush page.
Plant ownership
In June 2014, the Board of County Commissioners agreed to transfer the plant to the Discovery Clean Water Alliance, a regional sewer entity with four member agencies: Clark County, Clark Regional Wastewater District and the cities of Battle Ground and Ridgefield.
The transfer took place at the start of 2015, although Clark County will continue to operate the plant through 2024.
More information on the treatment plant is available on the Discovery Clean Water Alliance's website.
Related documents
- Discovery Clean Water Alliance capital plan (PDF)
- Operator agreement with Discovery Clean Water Alliance (PDF)
- Treatment plant's National Pollutant Elimination Discharge System permit (PDF)
- Primer for Municipal Wastewater Treatment Systems, U.S. Environmental Protection Agency (PDF)
