Protecting the Spokane Valley Rathdrum Prairie Aquifer, our sole-source drinking water supply, from pollution is the primary mission of Spokane County Environmental Services. Since the mid-1980s, Spokane County has developed a regional sewer system in the greater Spokane Valley area, protecting the drinking water supply by removing approximately 30,000 septic tank/drain field systems located above the aquifer. This ongoing effort is funded in-part by the establishment of an Aquifer Protection Area in the Spokane Valley region.
Aquifer Protection Area
Aquifer Protection Areas (APAs) are defined in Washington State Code RCW 36.36, and provide a mechanism for the creation of aquifer protection areas to finance the protection, preservation, and rehabilitation of groundwater, and to impose special assessments upon households within that area to finance facilities for such purposes. Spokane voters have twice passed ballot measures, once in 1988 and again in 2004, approving establishment of an APA in the Spokane Valley.
All of the details of the fee - how it is to be used and how much it costs property owners - can be found here in the approved resolution (PDF). The cost per household is $1.25 per month for water and $1.25 per month for sewer for a maximum of $30 per annum for 20 years. This is assessed as part of the property taxes.
If interested, here is the APA boundary map (PDF).