Cost

Notes

• Where the number comes from. The national price for interior basement waterproofing is $75 per linear feet — interior drain tile pricing published for 2026, $50–$110 per linear foot. Labor is about 60% of that. Cement Masons and Concrete Finishers near Federal Way, WA average $87,880 a year against a U.S. mean of $60,050 — a factor of 1.463 — so the labor half is scaled by that and the material half is not. Source: BLS OEWS May 2025 for the Seattle-Tacoma-Bellevue, WA metro area, SOC 47-2051.
• Why the city matters, not just the state. Trade pay moves inside a state as much as it does between states. Crews do not commute across a state to bid a job, and materials ship at national prices either way — so a metro wage is the honest input here and a state average quietly rounds four different cities into one number.
• What is in the price: breaking out the slab at the perimeter, the drain tile and gravel, a wall vapour barrier, re-pouring the concrete, a sump pit and pump.
• What is not: a battery backup pump, exterior grading and downspout work, foundation crack injection, and finishing the basement afterwards. These are the lines that turn a $9,586 quote into a $11,982 invoice, so ask about each one before signing.
• Use this as a bid check, not a quote. It prices an average job in average condition. Difficult access, the state of what is being replaced, the season, and a crew booked out three months all move the real number, and none of them are in a per-unit average.