King County Plumbing Permit — Who Can Pull One and What It Costs

Who Can Actually Pull a Plumbing Permit in King County

King County enforces one of the strictest permit-issuing rules in Washington: plumbing permits go exclusively to licensed plumbing contractors. Not general contractors. Not individual journeyman plumbers. Not architects or project managers acting on behalf of a property owner.

This catches people off guard because general contractors can pull their own structural, mechanical, and demolition permits in most jurisdictions. Plumbing is different. Under RCW 18.106.440, Public Health – Seattle & King County requires a valid L&I Plumbing Contractor license number and UBI before it will issue a permit. The contractor must also have an active designated plumber assignment on file with L&I and current insurance verification through the EBIPS portal.

The one exception is the homeowner exemption. If you own and occupy the residence as your primary home, you can pull a permit for work on that property — but only on owner-occupied single-family homes and duplexes. Rental properties, commercial spaces, and any new construction you plan to sell within 12 months are excluded from the exemption.

Seattle vs. Unincorporated King County

Seattle's Department of Construction and Inspections (SDCI) runs its own permitting system, separate from the King County permit center. The application forms, fee schedules, and inspection booking processes differ between the two, even though they enforce the same underlying plumbing code.

For unincorporated King County, permits go through the King County Department of Local Services. On December 10, 2025, King County migrated to its new Public Health Permit Center system, introducing 25 distinct permit types and ending the legacy billing grace period on January 1, 2026. Plan review costs increased under the new system, and — notably — like-for-like water heater replacements that were historically exempt now require a permit in the county system.

If your project straddles a city boundary or connects to a municipal utility district, you may need permits from both the city and the county (or the utility district itself for sewer and water main connections).

What a Plumbing Permit Application Requires

Regardless of which jurisdiction you file in, expect to provide:

• L&I Plumbing Contractor license number — the permit office verifies this against L&I's contractor database in real time
• UBI number — your Washington business registration with the Department of Revenue
• Scope of work description — fixture counts, pipe materials, DWV layout, and water distribution plan
• Site plan — showing the building footprint, utility connections, and any work outside the building envelope
• Proof of current insurance and workers' compensation coverage, if applicable — the contractor's insurance filings are submitted electronically to L&I through EBIPS; confirm the local permit office's exact document requirements

For larger projects — commercial buildings, multi-family structures, and any project that modifies the connection to a public sewer or water main — you'll also need engineered drawings and a separate utility connection permit from the municipal utility district (Seattle Public Utilities, Tacoma Water, etc.).

Common Reasons Permits Get Rejected

Three mistakes account for most rejections at the counter:

Expired or suspended contractor registration. L&I's system automatically suspends your contractor license if your annual renewal, insurance verification, or bond lapses. The permit office checks your status live, so a suspension that happened two days ago will block your application today.

Missing designated plumber assignment. Your contractor registration must have an active designated plumber on file with L&I. If your designated plumber left the company or let their certification expire, your registration is effectively incomplete — and the permit office will refuse to issue.

Incomplete scope of work. Vague descriptions like "replumbing kitchen" get kicked back. The permit office needs fixture counts, pipe sizing, and material specifications to route your application to the correct plan review track.

The Cost Question

Permit fees vary by jurisdiction and scope. Seattle SDCI uses a tiered fee schedule based on the number of fixtures and the type of work (new construction vs. retrofit). King County's new permit center charges separately for plan review and inspection, and the fees went up when the legacy billing system retired.

For a straightforward residential project — say, a bathroom remodel with 3–4 new fixtures — expect to pay somewhere between $150 and $400 in combined permit and inspection fees. Commercial projects with dozens of fixtures, fire suppression tie-ins, or medical gas systems run significantly higher.

The fees are trivial compared to the consequences of working without a permit. L&I can issue civil infractions against the contractor, and the building department can issue a stop-work order that halts the entire project — not just the plumbing scope.

How This Connects to Your License

If you're working toward your journey-level or master plumber certification, understanding the permit system matters for two reasons. First, hours worked while the contractor's L&I registration was suspended or inactive may be denied. Second, once you're ready to start your own plumbing business, the permit process is the final link in the chain — your L&I contractor registration, bond, insurance, and designated plumber assignment all have to be in order before a single permit gets issued.

The Washington Plumber License Guide walks through the full sequence from trainee card to contractor registration, including the designated plumber assignment and insurance requirements that unlock permit eligibility.

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