Best Basement Waterproofing Companies in Toronto

Toronto homes deal with a specific set of water problems. The clay-heavy soil across much of the city expands when wet, putting steady lateral pressure on foundation walls. Aging clay weeping tile systems and hard freeze-thaw cycles do the rest, which is why a wet basement is one of the most common repair calls in the city.

There are two main approaches: interior waterproofing redirects water that has already entered, channeling it to a sump pump through a perimeter drain; exterior waterproofing stops water before it reaches the wall by excavating down to the footing and applying a membrane and drainage board. Most reputable companies can do both, and the right choice depends on your foundation type, lot access, and how the water is getting in.

The nine companies below are real, currently operating businesses that genuinely serve Toronto homeowners.

1. Aquatech Waterproofing

Aquatech has operated in Toronto and the GTA since the mid-1990s, with multiple consecutive HomeStars Best of awards and a main office near Mount Dennis in the city's west end. They handle interior and exterior waterproofing, foundation crack repair, sump pump installation, and basement underpinning, which puts them in a different category from contractors focused only on moisture control.

The company offers a 25-year transferable warranty on eligible work. Their website is aquatechwaterproofing.ca.

2. RCC Waterproofing

In business since 1920, RCC is one of the oldest waterproofing contractors in Canada and has worked across Toronto neighbourhoods from Etobicoke and North York to East York and Scarborough. Services include interior and exterior waterproofing, weeping tile installation and replacement, foundation crack repair, sump pump work, and crawlspace encapsulation. Their exterior system uses hydraulic cement, rubberized membrane layers, drainage board, and new weeping tile down to the footing.

RCC backs waterproofing with a lifetime transferable warranty and has won the HomeStars Best of the Best award many times over. Their website is rccwaterproofing.com.

3. Dryshield Basement Waterproofing

Dryshield is a Canadian-owned contractor with over 25 years in the business, consistently well reviewed on Google and HomeStars, and a multiple-time HomeStars Best of winner. They cover both interior and exterior systems, foundation crack injection using polyurethane or epoxy resin, sump pump installation, and drainage work. Interior systems use vapour barriers, drainage channels, and sump hookups; exterior work involves full excavation to the footing with membrane and drainage board. They also offer 24-hour availability for emergencies.

Dryshield provides a lifetime transferable warranty. Their address is 60 Millwick Drive in North York. Website: dryshield.ca.

4. GJ MacRae Foundation Repair

GJ MacRae has served the GTA since 1975 as a second-generation family business, with more than 10,000 completed projects. They work year-round and their services include interior and exterior weeping tile systems, exterior membrane application, sump pump and sump box installation, structural underpinning, and full foundation wall replacement for severe failures. Their experience with poured concrete, concrete block, and stone rubble foundations is especially useful for older Toronto homes where the foundation material is not always predictable.

Their website is wetbasements.com.

5. Aquamaster Basement Waterproofing

Aquamaster has served the GTA since 2009 and has won the HomeStars Best of award for multiple consecutive years. Services cover interior and exterior waterproofing, foundation crack repair by epoxy or polyurethane injection, sump pump and backwater valve installation, and basement underpinning. The company is licensed, insured, and operates 24 hours a day for urgent calls.

A fully transferable 25-year warranty applies to eligible work. Their office is at 371 Front Street West, downtown. Website: aquamasterplumbing.com.

6. Act Fast Waterproofing

Act Fast has been active across the GTA for more than 25 years and focuses on interior waterproofing systems as their core offering, though they also handle foundation crack repair and sump pump installs. Their interior process cuts a perimeter trench in the basement floor, installs a 4-inch perforated weeping tile, and connects it to a sump pump or floor drain. They back the work with a 25-year transferable warranty and serve Toronto as well as Mississauga, Scarborough, Richmond Hill, and Hamilton.

Their website is actfastwaterproofing.ca.

7. Canada Waterproofers

Canada Waterproofers is a Toronto-based contractor with a solid HomeStars presence. Customers consistently describe straightforward, professional experiences on both targeted crack repairs and full drainage system installs. Services include interior and exterior waterproofing, crack injection, weeping tile replacement, and sump pump work.

Their HomeStars profile is a practical first stop for reading recent, job-specific reviews before calling.

8. Waterproofing Toronto

Operating at waterproofingtoronto.com, this company provides both interior and exterior services within the city and GTA. Exterior work includes crack filling, membrane application, and clay weeping tile replacement; interior work covers perimeter drainage systems tied to a sump pump. They are reasonably clear about what each approach accomplishes, which helps when comparing quotes from multiple contractors.

Website: waterproofingtoronto.com.

9. Toronto Basement Waterproofing

This company has operated under the domain torontobasementwaterproofing.com since 2004. Services include interior drainage systems, exterior membrane application, crack injection, and sump pump installation, all backed by a 25-year guarantee. Worth including in a quote comparison for interior system work in particular.

Website: torontobasementwaterproofing.com.

What to Look For in a Basement Waterproofing Company

Experience and Expertise

Toronto's housing stock ranges from century-old rubble-foundation rowhouses to mid-century concrete block and newer poured-concrete builds. Each type responds differently to water pressure and requires a different repair approach. A contractor with direct experience across these foundation types will diagnose your specific problem more accurately than one who applies the same solution to every job.

Licensing and Insurance

Any company excavating beside your foundation or breaking your basement floor should carry general liability insurance and WSIB coverage for their workers. Ask for proof of both before signing. Depending on scope, structural repairs can also trigger building permit requirements in Ontario, and a reputable contractor will be upfront about that rather than avoiding the topic.

Warranties and Reviews

A transferable warranty matters if you plan to sell the house. Read the warranty document before work starts to understand what triggers a callback and whether the coverage requires any maintenance on your part. On review platforms like HomeStars and Google, look for recent reviews that describe jobs similar to yours rather than relying on an overall score alone.

Tips for Hiring a Waterproofing Contractor in Toronto

Get Several Quotes

Waterproofing quotes vary widely, and the differences usually reflect genuine variation in scope and materials rather than arbitrary pricing. Getting three quotes on the same described problem helps you spot whether one contractor is proposing more work than the situation warrants, or whether a low number is skipping steps the others include. Be specific about what you see: where the water enters, whether it comes through the wall or the floor joint, and how long the problem has existed.

Ask Interior vs. Exterior

Interior systems are less disruptive and generally less expensive, but they manage water after it enters rather than stopping it at the foundation wall. Exterior systems address the root cause but require excavation and more time on site. Ask each contractor to explain their recommendation for your specific situation. A clear, direct answer is a good sign; a contractor who defaults to one approach for every job is worth questioning.

Confirm the Warranty in Writing

Get the warranty document before work begins. Common exclusions include pre-existing structural movement, modifications by other contractors, and failure to maintain the sump pump. Knowing what is and is not covered sets realistic expectations and protects you if the problem comes back down the road.

Explore the MSARCH directory for more vetted Ontario contractor guides.