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Plumbing and gas piping

Hire a registered contractor

Find guidance on hiring a registered contractor for plumbing and gas piping installations.

Inspections for plumbing and gas piping installations

Learn how to submit a request for an inspection, find an inspector, and view your results.


Find resources and tips on installing water heaters, gas piping, waste and vent pipe installation, and more.

Applications and permits

Learn how to submit a plumbing or gas piping plan review application or get a homeowner's permit.

Online services portal

Submit or check the status of permits, applications, and complaints.

Important notifications

King County Plumbing & Gas Program Feedback Survey

The purpose of this survey is to understand how we can improve our processes and services to increase customer satisfaction.

Plumbing, gas piping, and backflow device permits shall be obtained for each townhome

Effective March 22, 2021: A plumbing permit, gas piping permit, and backflow device permit shall be obtained for each townhome (single family home) that is constructed under 1 building (roof).

Download the related memorandum for details (35 KB).

Guidance for legionella and building water system closures

To prevent Legionella growth, these systems must be actively managed and maintained. See information and guidance to reduce Legionella growth and other pathogen and corrosion concerns that occur when there is a large drop in building water use.

Based on the current volume of plumbing plan submittals, first review comments for most projects are at approximately 4 to 6 weeks. Please note, very large or complicated projects may take up to 12 weeks. The allowance to request "Expedited Plan Review" is no longer in effect, however some project types (schools, daycares, low-income housing, etc.) are given priority review status.