Building permit

Short definition

A building permit (often issued as a “plumbing permit” sub-type for water and drain work) is the local building department’s authorization for a specific scope of plumbing work. In WA, permits are required for water heater replacements, repipes, sewer or water service replacement, gas-line work, new fixtures in new locations, and most additions. Like-for-like fixture swaps in the same location usually don’t need one — but always verify locally.

What it is

A permit is a written authorization from your local Authority Having Jurisdiction (AHJ) to perform a defined scope of work, with required inspections at specified phases. The AHJ in WA varies by location:

• Seattle: SDCI (Seattle Department of Construction and Inspections) issues plumbing permits. Side sewer permits moved to SPU on October 1, 2025.
• Tacoma: Tacoma Permits.
• Bellevue: City of Bellevue Development Services.
• Unincorporated King County: King County DLS.
• Spokane, Snohomish, Pierce: county or city building departments.

Most WA plumbing projects pass through three permit-related events:

1. Permit application and issuance. Contractor or homeowner submits scope, gets the permit number, pays fees.
2. Inspections. Underground (buried pipe), rough-in (in-wall before drywall), and finish (after fixtures).
3. Permit closure. Final inspection passes; the permit closes; the work is on the property record.

A permit is only “open” until it closes. An expired permit (no inspection activity in the permit window — typically 18 months in Seattle) can be re-opened or extended, but eventually shows up as a title defect.

Why it matters to a homeowner

Three big reasons.

Insurance. A leaking water heater that was never permitted may be denied coverage if your insurer asks for the permit number. Same for sewer-line failures, plumbing-installed-without-permit, and drain-line damage. The cost of permit fees ($50–$300 typically) is trivial against the cost of a denied claim.

Sale. WA title companies and lenders flag open or unpermitted work during sale. A bathroom that “just appeared” in tax records without a permit can require an estoppel inspection (retroactive permit) before closing — paid by the seller.

Safety verification. The permit is what brings the inspector on-site to verify code-required items: T&P relief valve, expansion tank where required, seismic strapping on water heaters, gas line sizing, drain slope, vent connections. The inspector is your cheap, expert second opinion on the contractor’s work.

When a contractor says “no permit needed for this” and you suspect they’re wrong, ask them to put it in writing. A reputable plumber will pull a permit if there’s any ambiguity. A contractor who pushes against the permit is usually trying to skip the inspection.

When you’ll encounter this term

• A water heater swap quote — permit fee should be a line item.
• A bathroom remodel scope — permits and inspections will be referenced multiple times.
• A title search on a home you’re buying — open permits flagged.
• An insurance claim adjuster asking for the permit number on the failed install.

Common variants and disambiguation

• Building permit vs. plumbing permit. In most WA jurisdictions, “plumbing permit” is a sub-type under the building-permit umbrella. SDCI issues a stand-alone “Plumbing Permit.” Same enforcement framework.
• Building permit vs. gas piping permit. Gas-line work often requires a separate mechanical/gas permit on top of the plumbing permit.
• Permit vs. inspection. A permit authorizes the work; an inspection verifies it. Both are required and they typically have separate fees.
• Owner-pulled vs. contractor-pulled. Some jurisdictions let homeowners pull permits on their own owner-occupied homes; others require a licensed contractor regardless. Ask the AHJ.

Common failure modes

• No permit pulled. Contractor skipped it; homeowner discovers years later at sale.
• Open permit (never closed). Inspections incomplete, permit expires; cleanup requires re-inspection or reapplication.
• Expired permit. Project paused too long; permit window lapsed. Re-issue or extend.
• Mismatched scope. Permit issued for “water heater replacement” but contractor also added an expansion tank without amending; inspector flags at finish.

Washington note

Permitting authority in WA is jurisdiction-specific — there is no single statewide “permit needed” list. Most jurisdictions follow a common pattern: replacement in the same location with no rough-plumbing change generally doesn’t need a permit (toilet swap, faucet swap, showerhead swap), while water heaters, repipes, sewer/water service, fixture relocations, and additions always do. Gas-line work is usually a separate mechanical permit.

For Seattle specifically as of 2025–2026:

• Plumbing permits are SDCI’s responsibility.
• Side sewer permits moved to SPU on October 1, 2025. Side-sewer work requires a SPU-registered contractor; homeowners cannot self-permit.
• Drainage System Development Charges (SDCs) became part of side-sewer permit invoicing starting January 1, 2026.

For King County water heater installs, the rule is unambiguous: every replacement requires a permit, and the inspector verifies T&P, expansion tank (closed system), two seismic straps, accessible location, and clearance. King County DLS publishes the requirements directly.

WA’s plumbing permits are enforced against the WA-amended UPC (WAC 51-56), the WA Mechanical Code (WAC 51-52, for gas), and the WA Energy Code (WAC 51-11C/R). The inspector is checking those code chapters specifically.

FAQ

How long does a plumbing permit take to get in Seattle?

A simple residential plumbing permit (water heater swap, single fixture replacement) typically issues same-day or next-day through SDCI’s online intake. More complex permits (basement bathroom, repipe, addition) may need plan review and take several weeks. Side sewer permits through SPU run 2–6 weeks depending on work scope.

How much does a plumbing permit cost in WA?

Fees range from roughly $50 to $300 for typical residential permits, depending on the scope and the jurisdiction. Seattle SDCI fees are higher than smaller WA jurisdictions. Side sewer permits in Seattle now run higher in 2026 with the new drainage SDC bundled into the invoice. Verify current fee schedules at the AHJ before quoting.

Can I pull my own permit as a homeowner?

In WA, most jurisdictions allow homeowners to pull permits on their own owner-occupied single-family residence — the “homeowner permit” path. The work still requires inspection and must meet code. Side sewer work in Seattle is the major exception: homeowners cannot self-permit; a SPU-registered side-sewer contractor must pull the permit.