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The 10 Best Basement Waterproofing Companies in Portland (2026)
Portland homeowners face frequent rain and seasonal storms, which makes dependable basement waterproofing an important local service. This list is built from Google review data and updated for 2026 using a Bayesian-style score that weights average ratings by the number of reviews, so businesses with both high scores and substantial feedback rise to the top. We focused on companies that appear in the Portland area search footprint and present a clear snapshot of who residents are recommending. Use this guide as a starting point to compare options, then contact companies directly for estimates and on-site assessments.
This ranking is computed from Google reviews (our method). Listings marked Partner are paid advertising spots: they sit alongside the ranking without changing its order.
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Better Basements and Waterproofing
Better Basements and Waterproofing earns the top spot because it pairs an excellent 4.9 Google rating with a large volume of feedback (251 reviews), giving it strong standing in our weighted ranking. Listed as a waterproofing service and based in Oregon City, the combination of high score and review count drives its Bayesian-weighted advantage over similarly rated firms. That balance of rating and review depth is why it leads this Portland-area roundup.
The full ranking
USA Roofing & Waterproofing LLC
USA Roofing & Waterproofing LLC holds a 4.9 rating from 214 reviews and appears under Roofing contractor; the address is in Portland.
214 reviews
Ability Plus Drainage Company
Ability Plus Drainage Company shows a 4.9 average with 198 reviews and is categorized as a Waterproofing service, located in Portland.
198 reviews
Foundations First Northwest
Foundations First Northwest posts a 4.9 rating across 185 reviews and is listed as a Construction company; the address is in Wilsonville.
185 reviews
NW Seismic
NW Seismic carries a 4.9 Google score from 91 reviews and appears under Construction company, with an address in Portland.
91 reviews
M Leon Construction
M Leon Construction has a 4.9 average based on 78 reviews and is categorized as a General contractor, listed in Portland.
78 reviews
Lavu Concrete
Lavu Concrete holds a perfect 5.0 rating from 17 reviews and is shown as a Concrete contractor, with a Portland address on NE 162nd Avenue.
17 reviews
Groundworks Foundation Repair Portland
Groundworks Foundation Repair Portland lists a 5.0 Google rating from 16 reviews and is categorized as a Waterproofing service; the address is in Canby.
16 reviews
Keystone Concrete Driveway Retaining Wall Foundation Contractor-Lake Oswego/West Linn
Keystone Concrete Driveway Retaining Wall Foundation Contractor-Lake Oswego/West Linn has a 4.9 rating from 21 reviews, is listed as a Concrete contractor, and references Lake Oswego/West Linn in its name while the address is in Portland.
21 reviews
TerraFirma
TerraFirma carries a 4.8 Google rating with a substantial 930 reviews and is categorized as a Concrete contractor; the business is located in Portland on SW Wall Street.
930 reviews
Frequently asked questions
How should I choose a basement waterproofing company in Portland?
Look for companies with consistently high ratings and a meaningful number of reviews, and verify they are experienced with local conditions. Ask for written estimates, timelines, warranties, and references, and confirm the contractor has appropriate licensing and insurance for your property.
What should I check before hiring a waterproofing contractor?
Confirm the scope of work is clearly spelled out, including specific materials and methods, cleanup, and any permits required. Request proof of insurance and ask to see recent project photos or references so you can assess workmanship and reliability.
When is it time to call a waterproofing or foundation professional?
Contact a professional if you notice persistent dampness, water pooling, musty odors, new or widening foundation cracks, or active leaks after heavy rain. Early assessment can prevent more extensive structural or mold-related issues.
How was this ranking of Portland companies created?
The list is generated from Google review data and updated for 2026 using a Bayesian-style approach that weights a business’s average rating by the number of reviews. That method favors high-rated companies that also have substantial customer feedback, offering a balance between score and sample size.