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Permit applications
Use the Online Services Portal to purchase plumbing, backflow assemblies, gas piping, medical gas permits, and submit Design Documents for Plan Review.
- Hire a registered contractor
- Fee schedule for plumbing and gas piping permits (192 KB)
- Please use the Online Services Portal to purchase permits. If you need to submit a hard copy of these applications, please print and mail the below applications to: Environmental Health Plumbing and Gas Piping Program, 401 5th Ave, Suite 1100, Seattle, WA 98104.
- Plumbing permit application (582 KB)
- Gas piping permit application (582 KB)
- Medical gas permit application (493 KB)
- Backflow permit application (349 KB)
Getting a homeowner's plumbing permit
Plumbing can be difficult. Public Health - Seattle & King County recommends you hire a professional plumber. If you choose to do your own plumbing, please adhere closely to the following instructions.
How to get a homeowner's plumbing permit
Plumbing can be difficult. Public Health - Seattle & King County recommends you hire a professional plumber. If you choose to do your own plumbing, please adhere closely to the following instructions.
When a permit is required
Whenever you are going to install, relocate, or change a plumbing or gas piping system, Seattle and King County codes require that you obtain a permit. PHSKC has jurisdiction in Seattle and unincorporated King County.
The permit issued to a homeowner is an authorization for the homeowner to do the plumbing. (See RCW 18.106.150) If you are being authorized by the property owner to apply for the plumbing permit, your signature on the permit application signifies that you have such authorization from the owner of the property. If a professional plumber is contracted with, they must be a registered contractor per Chapter 18.27 RCW.
Permit jurisdictions
PHSKC issues plumbing and gas piping permits, and performs inspections, in the following jurisdictions:
- Seattle
- Unincorporated King County
- Beaux Arts
- Clyde Hill
If the property is in another King County city, you will need to get your plumbing and gas piping permits from that city's building department.
If you are uncertain about the jurisdiction, please use the King County Parcel Viewer to check. Use care when entering the parcel number and property address for your permit. If our inspectors are sent to the wrong site due to your error, you may be charged a $25 change-of-address fee.
For permits issued online, you will need to wait for an hour before you can call to request an inspection.
Renewal of an existing permit or the addition of fixtures/outlets to an existing permit cannot be done online but you can do it over the phone. Call 206-263-9566 and have your SR# and a credit card available.
Notice: 2021 plumbing and gas piping codes
Effective March 15, 2024, projects in unincorporated King County will be required to be designed using the 2021 Washington State construction codes unless project building permit is vested in a previous code cycle.
The effective date of the 2021 Seattle construction codes has been postponed to November 15, 2024. Until the 2021 codes are officially adopted, PHSKC will accept applications for projects located within the City of Seattle using either the 2018 or 2021 suite of codes.
Check for ongoing updates: