In August 2005, EPA responded to the Site when EPA's Site Assessment Program provided information to the Response Program that two wells in the Deep Creek Community of Spokane County, Washington had trichloroethylene (TCE) in their drinking water above the federal drinking water standard of 5 parts per billion.
After conducting a thorough investigation of the Site, it was found that a total of three residential drinking water wells were contaminated with TCE above federal standards.
By September 2005, EPA installed three drinking water treatment systems (activated carbon) at individual residences in the affected area. Since 2005, EPA has been conducting quarterly sampling of the local ground water and water through the treatment systems to ensure effective performance.
In October 2007, after sampling of the pre-treatment, intermittent, and post-treatment water going throught the drinking water treatment systems it was found that one of three installed showed break through of the primary activated carbon filter. Due to this finding, filter change out and updated maintenance was initiated, as per the manufacturer's recommendations. In addition, while the other two treatment systems had not shown break through, filter change out and maintenance was also initiated in order to be efficient with contractor time, funding, and since it was unclear when these two other systems would show symptoms of filter break through. Based on an analysis performed on the installed systems, it was determined that filter change out and maintenance should be performed every 12-15 months.
As planned, the next filter change out and maintenance took place on April 21, 2009. This will be final change out and mainteance that EPA will conduct since the Washington Department of Ecology agreed to conduct one filter change out as the project transitions back to local control.
