Short definition

Choosing a plumber in Washington means verifying their L&I plumber certification, plumbing contractor registration, $6,000 bond, $250,000 general liability insurance, and active workers’ comp before signing anything. The L&I Verify portal at secure.lni.wa.gov/verify is the single source of truth — Yelp ratings are not verification.

What it is

Washington runs a two-track licensing system. The individual plumber holds an L&I certification (PL01 journey-level, PL02 residential, PL04 residential service, plus specialty tiers — see licensed plumber). The business holds a separate plumbing contractor registration under RCW 18.106 — a distinct statute from general contractor registration (RCW 18.27). Both must be active for legal residential work.

The contractor’s registration requires:

  • $6,000 surety bond (or assigned savings)
  • $250,000 combined per occurrence general liability insurance, with L&I as certificate holder
  • Designated journey-level or specialty plumber on staff
  • 24-month renewal cycle

A “general contractor” or “handyman” doing plumbing work directly — without a separate plumbing contractor registration — is operating outside their license.

Why it matters to a homeowner

Six load-bearing scam-prevention angles for any WA plumbing hire:

1. Verify both the individual and the business

“Yes, I’m licensed” without showing a card is not enough. Ask for the L&I plumber certification number and the plumbing contractor registration number. Run both at secure.lni.wa.gov/verify before signing anything. If the contractor refuses, or “the license is in my name, the registration is under my brother’s company,” that’s a red flag.

2. Door-to-door cancellation right

WA RCW 63.14.154 plus the FTC Cooling-Off Rule (16 CFR Part 429) give you 3 business days to cancel a door-to-door contract over $25. Saturday counts; Sunday and federal holidays don’t. The seller must give you the written cancellation form. Door-to-door pitches for “we noticed your roof / sewer / water heater needs work” are heavily over-represented in scam patterns.

3. “We don’t need a permit” is usually wrong

For major plumbing work in WA — fixture relocation, repipe, water heater replacement, gas appliance install, sewer work — permits are required even when the homeowner does the work themselves under RCW 18.106.150 exemption. Verify with the local AHJ if a contractor claims “no permit needed” beyond like-for-like fixture swaps.

4. Drywall before rough-in inspection is the biggest red flag

The single most common scam pattern in residential plumbing: a contractor closes walls before the rough-in inspection, hiding non-compliance. The proper sequence is rough-in plumbing → rough-in inspection → drywall. Period. See rough-in inspection stages.

5. RCW 60.04 mechanic’s lien survives your payment to the prime

Subcontractors retain lien rights against your property even after you’ve paid the prime contractor. If your prime hasn’t paid the subs, the subs can lien your home. Lien-release docs at every progress payment are the protection. “I already paid the contractor” is not a defense.

6. Verify the permit was actually pulled

Before the plumber arrives, verify the permit number on the AHJ portal. Seattle SDCI, Tacoma Permits, Bellevue Development Services, and county permit portals are public. “We’ll get the permit number back to you after we start” is a flag.

When you’ll encounter this term

  • A contractor’s quote ready to sign.
  • A side-sewer replacement project requiring a registered side-sewer contractor (Seattle SPU keeps a separate list).
  • A door-to-door pitch — invoke the cooling-off period, get other quotes.
  • A pre-purchase inspection finding undocumented work — verify with AHJ permit history.

Cost data

  • L&I license verification: free.
  • Service-call dispatch (Seattle / Tacoma 2026): $50–$150 (often credited toward work).
  • Hourly residential labor: $100–$200/hr; specialty (sewer, hydronic, gas) $150–$300/hr.
  • Annual maintenance walk-through: $150–$400.

Washington note

WA L&I plumber contact: 360-902-5207, [email protected]. Side-sewer work in Seattle requires a registered side-sewer contractor — SPU maintains a separate list. Tacoma uses a similar registered list through Tacoma Permits. The homeowner exemption (RCW 18.106.150) does not extend to plumbing work on rental, for-sale, or for-lease properties.