Spokane County is doing too little to protect lakes and rivers from human septic waste, a state panel charges.
The Washington Growth Management Hearings Board is ordering the county and the state Department of Ecology to tighten regulations of new septic tank systems along shorelines in unincorporated portions of the county.
The shoreline program strictly regulates development near waterways and provides shoreline buffers along the Spokane River and lakes and streams under county jurisdiction.
The hearings board found that the septic tank regulations adopted by the county and approved by the Ecology Department are too weak given the amount of current scientific research showing that phosphorus from on-site sewage systems can leach into water bodies.
Spokane County has until May 23 to comply with the hearings board order.
The order involving septic tanks was one of six issues raised in the shoreline appeal brought to the hearings board by Futurewise, Spokane Riverkeeper, the Lands Council and Trout Unlimited.
The board rejected five other issues in the appeal.
Five years ago, the county tried to adopt a considerably weaker shoreline master program than the 1975 original version, but the state Ecology Department intervened and rewrote entire sections, forcing the county to accept the stronger regulations. The state then approved the update last winter.
On the septic tank issue, the board found that “increased phosphorus inputs to shoreline ecosystems result in net loss of ecological functions.”
Human-related phosphorus has been documented for years as polluting the Spokane River.
In the shoreline update, the county deferred to local and state health agencies for regulating septic tank systems.
But the Spokane Regional Health District does not specifically regulate phosphorus leaching or migration from on-site sewage systems, the board found.
In particular, there was no clear requirement in the shoreline update regarding the vertical distance required to separate drain fields from groundwater beneath them. Previously, the county required that the septic tank drain fields be at least 10 feet above the highest groundwater level at the shoreline building site.
The lack of that specific regulation is a violation of the state shorelines law because of the risk of phosphorus leaching into waterways, the board said.
John Pederson, county planning director, said the county has 30 days to file an appeal, but no decision had been made on whether to file one.
County Commissioner Todd Mielke said the county had relied on guidance from the Ecology Department in writing its regulations of septic tanks near shorelines.
He said he was pleased the hearings board upheld the county’s position in the five other appeal issues, involving protection of channel migration zones, greater public access along residential development, environmental critical areas along shorelines, fish and wildlife habitat and regulation of trails.
Pederson said developing the new shoreline program involved “a tremendous amount of technical data.”