Grant County, WA Environmental Rules: Erosion Control (2026)

080, Clearing, Grading and Drainage Standards, governs erosion and sediment control on every development project in unincorporated Grant County. 08. Subsection (b) extends that duty to stormwater specifically: runoff from a development cannot adversely affect offsite property, surface water quality and quantity, or critical areas, and the developer must make provisions to control the release of surface water both during and after construction. Subsection (c) supplies the technical benchmark: clearing, grading, drainage, and erosion control measures must conform to the Washington State Department of Ecology's Stormwater Management Manual for Eastern Washington, or to whatever the County Engineer specifies instead, which functions as the county's working construction-site erosion standard even though the manual itself is a state document adopted by reference.

Subsection (d) adds a results-based duty, that soil erosion and sedimentation of drainageways be controlled so as to prevent damage to adjoining property and downstream drainage channels and receiving waters, and later subsections give the County Engineer authority to require a sealed drainage report from a professional engineer and to condition permit approval on meeting these controls, with the Engineer's approval or rejection of a drainage report final and not subject to administrative appeal.