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Department of Permitting and Environmental Review

Department of Permitting and Environmental Review
35030 SE Douglas St., Ste. 210
Snoqualmie, WA 98065-9266

Phone: 206-296-6600
TTY Relay: 711

Service Center Hours

Septic systems, wells, plumbing and drainage FAQ

Who should I contact for septic system (including drainfields), well, or plumbing questions?

Contact Public Health - Seattle & King County at 206-477-8050 for questions related to septic systems, drainfields, wells and plumbing.

Also contact Public Health with as-built (septic system 'maps'), gas piping, pump and septic tanks, and OSS (on-site sewage systems) questions.

Please refer to information Public Health offers about septic systems at and plumbing permits at

Note: These Public Health services and Environmental Health staff are located in Eastgate.  Customers may also communicate with Public Health’s Sanitarian-of-the-Day at the DPER office building in Snoqualmie on Tuesday, 7:30 - 11:30 AM and Thursday, 1:00 - 3:00 PM.


Where can I find small project drainage review information?

Small project drainage review is an alternative to full drainage review for small residential building, clearing, subdivision projects or small agicultural projects that result in 10,000 square feet or less of impervious surface added on or after January 8, 2001, or less than 4% of total impervious surface as defined by Section of the King County Surface Water Design Manual.

Please refer to Small Project Drainage Requirements (PDF*, 2.2MB), Appendix C of the Surface Water Design Manual, for detailed information.

For an overview of drainage review processes, see the Permitting Department Customer Information Bulletin #29, Drainage Review (PDF*, 139KB).

For more about the King County Surface Water Design Manual, go to


Who should I contact for drainage complaints?

For drainage complaints involving flooding (water drainage, retention, or runoff other than road related) and water quality, contact the Drainage and Water Quality Complaint Investigation Line of the King County Department of Natural Resources and Parks, Water and Land Resources Division, at 206-477-4811.

Please see detailed information at

For road drainage and maintenance problems in any unincorporated area, call 206-296-8100 or toll-free at 1-800-KC-ROADS (1-800-527-6237). Detailed roads information is online at


*Note: To view PDFs, free software from Adobe is required. See helpful hints for assistance.

To request this information in alternate formats for people with disabilities, call 206-296-6600 or TTY Relay:  711.