#1 · SEATTLE
Full sewer line replacement swaps the entire side sewer — the fix for collapsed lines, chronic root damage, bad slope, and Orangeburg pipe. It's the biggest-ticket residential plumbing job, so method choice (trenchless vs open trench) drives the price.
Wet-side market range — get itemized quotes before work starts
Companies whose focus matches this work are listed first, then Seattle's other top-rated plumbers. Same no-pay-to-play ranking as everywhere on Wetside Plumbing — the formula.
Google Business data, 2026-08-07. See the full Seattle ranking →
Also searched as: expert sewer installs, mainline replacement, replace sewer, replacing sewers, sewer installation, sewer installs.
Trenchless jobs commonly finish in 1–2 days. Open-trench with street cuts and restoration can run a week. Either way, you'll typically have service each evening.
Make them itemize it. Side sewer permits, city-main connection, and pavement restoration are exactly where five-figure surprises live. Our sewer cost guide lists the questions to ask.
Ask for their Washington L&I contractor number and verify it at secure.lni.wa.gov/verify — active license, bond, and insurance. Listings above with a green badge are ones we've already matched to an active license in state records.