Cost to Basement Waterproofing in Seattle, WA

$2,816–$15,360 in Seattle

28% above the national average · 1.28x cost multiplier

In Seattle, a basement waterproofing runs $2,816 to $15,360 on average — about 28% above what homeowners pay nationwide. The West Coast market's labor costs account for most of the gap, with material pricing and local permitting fees adding to the spread. Use the cost table below to compare budget, mid-range, and premium options side by side.

Cost Breakdown in Seattle

Line Item	Low	Mid	High
Cost per sq ft	$4	$8	$15
Materials	$640	$3,200	$10,240
Labor	$512	$4,480	$12,800
Permits	$0	$384	$640
Total	$1,152+28% vs. national avg	$8,064+28% vs. national avg	$23,680+28% vs. national avg

Budget

Interior waterproofing paint/sealant on walls, minor crack injection, improved grading around foundation. DIY-friendly exterior fixes.

Mid-Range

Interior French drain system with sump pump, or exterior waterproofing membrane on one wall. Addresses moderate water intrusion.

Premium

Full perimeter interior drainage system, battery backup sump pump, full exterior excavation and membrane on all walls, French drain, and discharge piping.

Material Options

Material prices below are national averages; availability in Seattle may shift costs slightly.

Material	Cost/Unit	Pros	Cons	Best For
Waterproofing Paint/Masonry Sealer	$0.50-$2/sq ft applied	Lowest cost, DIY-friendly	Only works on minor dampness, not active water intrusion	Slight wall dampness, minor condensation issuesLowest cost, DIY-friendly
Interior French Drain System	$50-$100/linear ft of perimeter	Effective at managing water, less invasive than exterior	Water still enters foundation, requires ongoing sump pump maintenance	Most common solution for water intrusion in finished or unfinished basementsEffective at managing water, less invasive than exterior
Exterior Waterproofing Membrane	$8,000-$25,000 whole-house	Stops water at the source, most thorough solution	Requires full excavation, most expensive option	Severe water problems, new construction additions, comprehensive permanent fixStops water at the source, most thorough solution
Epoxy/Polyurethane Crack Injection	$100-$500 per crack	Permanently seals individual cracks, targeted fix	Only addresses specific cracks, not widespread seepage	Isolated foundation cracks with water intrusionPermanently seals individual cracks, targeted fix
Drainage Board and Dimple Mat	$2-$5/sq ft installed	Creates a drainage gap between foundation wall and interior space	Must connect to drainage system to be effective	Wall drainage in partially waterproofed basementsCreates a drainage gap between foundation wall and interior space

Other Projects in Seattle

Full Kitchen Remodel

Full Bathroom Remodel

Composite Deck Building

Back to national average for Basement Waterproofing

Seattle Estimate

Typical Range

$2,816–$15,360

vs. National Average

28% above national

Cost Multiplier

1.28x

Cost Per sq ft

$4–$15

Estimates apply Seattle's 1.28x regional cost multiplier to national averages. Actual bids vary by contractor, project scope, and timing.

See national average costs →