Environmental Rules in Chelan County, WA (2026)
5 rules for unincorporated Chelan County, Washington.
Verified from official government sources
Stormwater Management
Chelan County bans dumping anything but stormwater into its municipal separate storm sewer system in the unincorporated county. Section 13.14.050 prohibits illicit discharges and illicit connections to the storm drain system, carving out only specific exceptions like diverted stream flows and dechlorinated pool water. Chapter 13.16 separately adopts the Stormwater Management Manual for Eastern Washington to govern runoff from new development and land-disturbing activity, with Public Works and Community Development sharing enforcement.
Chelan County Stormwater Discharge and Drainage Rules
Some RestrictionsChelan County Code § 13.14.050
No person shall throw, drain, or otherwise discharge, cause, or allow others under its control to throw, drain, or otherwise discharge into the MS4 any pollutants or waters containing any pollutants, other than stormwater. The commencement, conduct or continuance of any illicit discharge to the storm drain system is prohibited except as described as follows: ... Car washing is not prohibited, b...
Erosion Control
Land-disturbing projects of one acre or more in unincorporated Chelan County must prepare and implement a construction stormwater pollution prevention plan (SWPPP) before breaking ground. A certified erosion and sediment control lead must be on site or on call whenever grading occurs, per Chelan County Code Chapter 13.18.
Erosion & Sediment Control, Unincorporated Chelan County
Some RestrictionsChelan County Code § 13.18.040
Core Element No. 2: ... Construction Stormwater Pollution Prevention. ... Construction stormwater pollution prevention plan required: A stormwater pollution prevention plan containing all appropriate information as specified in this chapter shall be submitted to Chelan County ... Projects meeting the regulatory threshold of land-disturbing activities of one acre or greater shall prepare, submit...
Flood Zones
In unincorporated Chelan County, no one may start construction or fill in a special flood hazard area without a floodplain development permit from Community Development. The permit covers structures, manufactured homes and fill activity alike. Inside the mapped regulatory floodway, new construction and substantial improvements are barred outright unless an engineer certifies zero rise in flood levels under Chelan County Code Chapter 3.20.
Chelan County Floodplain Development Permit Rules
Significant RestrictionsChelan County Code §§ 3.20.130, 3.20.300
A development permit shall be obtained before construction or development begins within any area of special flood hazard established in this chapter. The permit shall be for all structures including manufactured homes, as set forth in Section 3.20.120, Definitions, and for all development including fill and other activities, also set forth in Section 3.20.120, Definitions. ... No Rise Standard....
Defensible Space
Chelan County's critical areas code lets an owner of a legally built structure request vegetation removal for defensible space inside a wetland, habitat or geologic-hazard buffer. Chelan County Code § 11.77.040(2)(F)(iv) requires the administrator to weigh fire-risk reduction against habitat impact before approving the clearing.
Defensible Space in Critical Areas, Chelan County
Some RestrictionsChelan County Code § 11.77.040(2)(F)(iv)
Fire Protection. ... Property owners with legally established existing structures may request fire protection measures which are recommended through an adopted wildfire protection plan or from the Washington Department of Natural Resources, Cascadia Conservation District, or other similar group/agency. These provisions are intended to support fire suppression protection and shall not be used fo...
Flood Elevation Requirements
New construction and substantial improvements in Chelan County's special flood hazard areas must raise the lowest floor, including any basement, at least three feet above the base flood elevation for residential structures, and at least one foot above it for commercial, industrial and other nonresidential structures, under Section 3.20.260.
Flood Elevation Standards in Unincorporated Chelan County
Some RestrictionsChelan County Code § 3.20.260(1)(A), (2)(A)
In all areas of special flood hazard where base flood elevation data has been provided as set forth in Section 3.20.090, Flood hazard areas established, or Section 3.20.100, Use of other base flood data, the following provisions are required: ... Residential Construction. (A) New construction or substantial improvement of any residential structure shall require the lowest floor including baseme...
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