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Plumbing and gas piping applications and permits
Learn how to submit a plumbing or gas piping plan review application or get a homeowner's permit.
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 (109 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)
Plan review information
A plumbing plan review must be completed by Public Health - Seattle & King County (PHSKC) for certain occupancies.
- Check to see if your project requires plan review: Occupancy and Use (122 KB)
- Note: Certain projects such as schools, daycares, and low-income housing qualify for priority review. If you believe your project may qualify, please send an inquiry to planreviewinfo@kingcounty.gov to confirm.
- Follow these instructions to submit an application for plan review (347 KB).
- View the information you are required to provide as part of your plan review submission:
- Download Plumbing Design Guidance (253 KB).
- Find links to helpful information such as water disinfection requirements, system-specific documentation, affidavits, and design guidance for specific occupancy types:
- Download Schedule A (242 KB).
- Application form for Alternate Material, Methods or Modifications (AMMRF, 207 KB)
- Note: To prevent data loss, download the blank form and save to your local network or computer's hard drive prior to filling out. Save a copy of your filled out form before submitting.
- Medical gas categories and definitions
For questions about the plumbing plan review process, please email planreviewinfo@kingcounty.gov.
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
- Beaux Arts
- Clyde Hill
- Unincorporated King County
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.