This guide compares 23 waterproofing companies serving Ottawa. The featured shortlist includes Summit Drain & Plumbing (5.0 stars from 127 Google reviews), Wet Basement Solutions (5.0 stars from 126 Google reviews), and The Foundation Experts Inc. (5.0 stars from 27 Google reviews).
Listings claimed by their owner appear first; all other positions follow the published rating methodology. 22 carry a sourced public rating, averaging 4.8 stars; the highest-rated is D'Agui Masonry Ottawa at 5.0 stars from 215 Google reviews.
A wet or leaky basement in Ottawa is common, thanks to clay soil and a hard freeze-thaw cycle, and the fix depends entirely on finding the real source of the water first. The best waterproofing companies diagnose before they seal, whether the cause is grading, weeping tile, or a cracked foundation, and they warranty the result.
The companies below handle wet and leaky basements: interior and exterior waterproofing, foundation crack repair, sump pumps, and drainage across the city. Each is a real Ottawa business with public reviews you can read, so you can compare diagnosis, methods, and warranty before you spend on a fix that has to actually keep water out.
Also covers: Wet basement · Leaky basement · Foundation crack repair · Sump pumps · Drainage
Featured professionals
A focused Ottawa shortlist. Listings claimed by their owner appear first; all other positions follow our published rating methodology.
Listings claimed by their owner appear first. All other positions follow the selected sort.
FeaturedClaimedKanata +7
5.0(126)on GoogleChecked Aug 2026Basement WaterproofingWaterproofing and foundation-repair company established in 2008, based in Carleton Place and serving the Ottawa Valley and Eastern Ontario. Offers a lifetime warranty and free quotes.
View Wet Basement Solutions
FeaturedKanata
5.0(127)on GoogleChecked Aug 2026Basement WaterproofingKanata-based waterproofing and plumbing company (BBB A+) handling foundation waterproofing, weeping tile, sump pumps and drain/sewer work. Offers 24/7 emergency service.
View Summit Drain & Plumbing
Orléans +3
5.0(27)on GoogleChecked Jul 2026Basement WaterproofingOttawa foundation-repair and waterproofing company operating since 1995 and BBB A+ accredited. Offers a 25-year transferable warranty on waterproofing work.
View The Foundation Experts Inc.More basement waterproofing
FeaturedD'Agui Masonry Ottawa is a masonry contractor in Ottawa. Rated 5 from 214 Google reviews.
View D'Agui Masonry Ottawa
FeaturedBraden Foundation Construction is a waterproofing service in Ottawa offering concrete work and drainage. Rated 5 from 105 Google reviews.
View Braden Foundation Construction
Ottawa Masonry & Parging Contractors is a masonry contractor in Ottawa offering building restoration. Rated 5 from 82 Google reviews.
View Ottawa Masonry & Parging Contractors
FeaturedStonehenge Masonry is a masonry contractor in Ottawa. Rated 4.9 from 131 Google reviews.
View Stonehenge Masonry
Barrhaven +4
4.9(70)on GoogleChecked Aug 2026PlumbersDr. Pipe Drain and Plumbing is a plumber in Ottawa offering bathroom renovation, drainage and hot water systems. Rated 4.9 from 70 Google reviews.
View Dr. Pipe Drain and Plumbing
FeaturedEC Foundations is a concrete contractor in Ottawa offering waterproofing. Rated 4.9 from 60 Google reviews.
View EC Foundations
Nepean
4.8(124)on GoogleChecked Aug 2026Concrete & MasonryColiseum Concrete & Interlock is a concrete contractor in Nepean, Ottawa. Rated 4.8 from 124 Google reviews.
View Coliseum Concrete & Interlock
Gloucester
4.9(56)on GoogleChecked Aug 2026Basement WaterproofingTirenio Parging is a concrete contractor in Gloucester, Ottawa offering masonry. Rated 4.9 from 56 Google reviews.
View Tirenio Parging
Ottawa Foundation Repair is a waterproofing service in Ottawa offering concrete work and septic systems. Rated 4.8 from 98 Google reviews.
View Ottawa Foundation Repair
Nepean
4.9(48)on GoogleChecked Aug 2026FencingMedusa Stoneworks is a fence contractor in Nepean, Ottawa offering concrete work and landscape design. Rated 4.9 from 48 Google reviews.
View Medusa Stoneworks
Solid Masonry is a masonry contractor in North Gower, Ottawa. Rated 5 from 29 Google reviews.
View Solid Masonry
Ardel Concrete Services is a concrete contractor in Ottawa. Rated 4.9 from 38 Google reviews.
View Ardel Concrete Services
Barrhaven +8
5.0(23)on GoogleChecked Aug 2026Concrete & MasonryKavanagh Masonry is a masonry contractor in Stittsville, Ottawa. Rated 5 from 23 Google reviews.
View Kavanagh Masonry
Donovan Complete Masonry is a masonry contractor in Ottawa offering chimney sweeping. Rated 4.8 from 54 Google reviews.
View Donovan Complete Masonry
Kanata +7
5.0(15)on GoogleChecked Aug 2026Basement WaterproofingFoundation repair and waterproofing company serving Ottawa, Gatineau and Kingston. Covers interior and exterior waterproofing, crack repair, weeping tile and flooded-basement solutions.
View Pro-Core FoundationsBarrhaven +8
5.0(13)on GoogleChecked Aug 2026Basement WaterproofingJust Foundations is a waterproofing service in Ottawa. Rated 5 from 13 Google reviews.
View Just Foundations
Gloucester +3
4.4(82)on GoogleChecked Aug 2026Basement WaterproofingOttawa foundation and waterproofing contractor operating since 1992, offering a 10-year transferable written warranty. Handles basement waterproofing, foundation crack and structural repair, and crawl space encapsulation.
View Mr. Foundation Inc.
Nepean
4.1(23)on GoogleChecked Aug 2026Basement WaterproofingOttawa Structural Residential Services Ltd is a foundation in Nepean, Ottawa offering waterproofing. Rated 4.1 from 23 Google reviews.
View Ottawa Structural Residential Services Ltd
Nepean +4
4.3(208)on GoogleChecked Aug 2026Basement WaterproofingLong-running basement waterproofing and foundation-repair firm serving the greater Ottawa region since 1978. Offers a transferable lifetime dry-basement warranty.
View The Foundation Guys Inc.
Nepean +2
Basement WaterproofingOttawa-area waterproofing company covering interior and exterior basement waterproofing, weeping tile, sump pumps and backwater valves. Provides a 3-year labour warranty and free online quotes.
View iBasementsWet basements in Ottawa
Before an excavation is quoted, two things are worth knowing. Ottawa has a rebate programme for the devices that stop sewage backing up into a basement, and the by-law is specific about which sewer a sump pump may discharge into. Both change what a sensible scope of work looks like.
Ottawa's Residential Protective Plumbing program provides financial assistance to qualified property owners for installing protective plumbing devices. The devices named are indoor sanitary backwater valves, storm backwater valves, outdoor storm backwater valves, and primary or secondary sump pumps with battery backup power, with a higher rebate where a sump pit has to be constructed rather than reused.
Rebate amounts change, so read them from the City's page rather than from a quote that cites them. What matters before you sign is whether the proposed work is eligible at all, and that is a question with a published answer.
The battery backup is not a detail. Ottawa's heaviest rain arrives with the storms most likely to take the power out, which is the hour a mains-only pump stops being a pump.
Ottawa's Sewer Use By-law prohibits discharging stormwater, water from the drainage of roofs or land, water from a watercourse, or uncontaminated water to a sanitary or combined sewer except in the circumstances the by-law sets out. A sump pump plumbed into the household drain is the common way that rule gets broken.
The other direction has its own prohibition: nothing may be discharged into a storm sewer, a watercourse, or a private connection to a storm sewer where it has the characteristics the by-law lists, and the person who discharges is responsible for the cost of investigating, repairing or cleaning any damage to the sewage works.
So the discharge route is part of the design, not an afterthought. Ask where the pump will send water and how far from the foundation it lands, because water returned to the same soil is water the pump will move again.
Exterior waterproofing means digging along the foundation, and requesting a locate through Ontario One Call is free and required by law before digging begins. Infrastructure owners have five business days to complete a locate for a single civic address, and ten for an advanced request.
Ontario One Call notes the law sets those deadlines without guaranteeing them. A contractor who can start this week has either already requested the locate or has not thought about it, and that is a fair question to ask.
Sources, checked 2026-09-18:
Buyer guide
What separates a great waterproofing company from a cheap quote, and the questions worth asking before you sign.
Sealing a wall without finding the source often just moves the leak. A good contractor traces whether it is grading, weeping tile, or a crack before quoting a fix.
Interior systems manage water that gets in; exterior excavation stops it at the wall. They solve different problems at very different costs. Ask which your situation actually needs.
Ottawa's spring melt tests every sump pump. Ask about a battery or water-powered backup so it keeps running through a storm outage.
Waterproofing should come with a transferable warranty. Confirm its length and exactly what it covers, since a dry basement is the whole point.
assessed in spring, work done April to November
Ottawa's ground freezes through the winter and releases that water when it thaws, so spring is when a basement tells you the truth about itself. Excavation needs unfrozen ground, which rules out roughly December to March, when the daily average sits at or below 0 °C. A leak found during the March thaw is normally addressed in the months immediately after it.
Temperatures are the Environment and Climate Change Canada: Canadian Climate Normals for station OTTAWA CDA, 1991-2020. Checked 2026-09-10. Any single year can run warmer or colder than the normals.
Before you hire
The City of Ottawa runs a Residential Protective Plumbing Program offering rebates toward sump pumps and backwater valves, and it publishes the eligibility rules, the amounts and the deadline that applies. A homeowner hiring this trade can be owed money by the City without knowing it.
Ottawa Service Directory is a listings site, not a regulator: we publish what a business reports about itself, so confirm what applies to your job with the source below and with the business before work starts.
Source: City of Ottawa: Residential Protective Plumbing Program rebate. Checked 2026-08-24. Rules and thresholds change, so confirm before work starts.
Common questions
For homeowners
Tell us about the job and someone on our team finds you a suitable Ottawa waterproofing company.