Top-rated basement waterproofing pros.

Best basement waterproofing pros near Cos Cob, CT

Enter your zip and get matched with up to 5 pros

TRUSTED BY COS COB, CT HOMEOWNERS

  • Average homeowner rating star icon4.7
    Average homeowner rating
  • Verified reviews icon46
    Verified basement waterproofing services reviews

Top-Rated Basement waterproofing pros in Cos Cob - Updated Nov 2026

Avatar for American Dry Basement Systems, LLC
American Dry Basement Systems, LLC
4.9(
118
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Cos Cob, CT and surrounding areas

Approved

In business since 1997

Free estimates

Credit card accepted

"I had my basement waterproofed almost 3 years ago by them and I had no issues since then with the basement flooding regardless of how much it rains. I highly recommend using American Dry Basement!"
Drainage Trench
Jackhammer
Mixing SuperCrete
Compress Wash Stones
Spreading SuperCrete

+7

Response time11 hrs
3 neighbors recently requested a quote
Recommended by66%of homeowners
Avatar for Dirty Deeds Basement Waterproofing
Dirty Deeds Basement Waterproofing
5.0(
4
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Cos Cob, CT and surrounding areas

Approved

In business since 2012

Free estimates

Emergency services offered

"Dean and his crew were professional, reliable, extremely neat/clean and went above and beyond, often, to make the sure work was completed to my satisfaction. They did small things not even required to make sure the entire basement area was much more than even expected. The basement has never been so dry in the 40 years I have lived here. I would hire them again in a heartbeat."
Additional Photos
Additional Photos
Additional Photos
Additional Photos
Additional Photos

+24

Response time7 hrs
7 neighbors recently requested a quote
Recommended by100%of homeowners
Avatar for Groundworks
Groundworks
4.9(
13
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Cos Cob, CT and surrounding areas

Approved (Corporate)

Super Service Award Winner

In business since 2025

Free estimates

Warranties offered

Groundworks is the North America's leading and fastest-growing foundation repair and water management solutions provider. Groundworks is a vertically integrated company with its own manufacturing operations and a world-class software solution, allowing us to serve our customers more effectively. From the first phone call to the annual maintenance offered, our customers have peace of mind knowing we're there with one mission to repair, protect and improve their home. For state licenses visit Groundworks.com/licensing

Foundation
Foundation
Foundation
Concrete
Concrete

+16

442 neighbors recently requested a quote
Avatar for AG Property Maintenance, LLC
AG Property Maintenance, LLC
4.6(
12
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Cos Cob, CT and surrounding areas

Approved

In business since 2012

Free estimates

Offers commercial services

"Pedro and team solved an ongoing pond drainage issue that was able to be resolved. Many companies came and charged us money for half a job and this was not the case with AG. They were professional, proficient and quickly got to the source of the problem in one day. Prices were fair and they did not have to come back as they had all the supplies they needed to start and finish the job which is very rare for a major culvert issue like this one."
Brookfield ct
Brookfield ct
Brookfield ct
Brookfield ct
Brookfield ct

+4

Response time2 days
3 neighbors recently requested a quote
Recommended by100%of homeowners
Avatar for AA Outdoor Services, LLC
AA Outdoor Services, LLC
3.9(
33
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Cos Cob, CT and surrounding areas

Approved

In business since 1990

Free estimates

Small jobs welcome

"Vincent did an absolutely beautiful job on my cement and asphalt driveway. Their craftsmanship was top-notch. They finished the job quickly, and left the work area clean when they were not there. They stayed in touch throughout the process, and they take tremendous pride in their work. I have worked with hundreds of contractors over the years and these folks are among the very best and most reliable. Cannot say enough good things, also the prices were competitive, and they delivered a better quality of work than I would expect for a similar price."
Driveway in New Haven (West Haven)
Rear entrance and parking area (West Haven)
Rear entrance and parking area (West Haven)
Step repair (West Haven)
Step repair (West Haven)

+61

Response time9 hrs
Recommended by100%of homeowners
...
Showing 1-10 of 195
Basement Waterproofing FAQs, answered by experts

The primary downside to crawl space encapsulation is the high cost, which can be several thousand dollars. Additionally, the process can make future repairs more complicated by limiting access to plumbing and electrical wiring within the crawl space. Encapsulation also requires sealing off any vents, which can be a disadvantage for home designs that benefit from the airflow they provide. It's recommended to consult with a crawl space contractor to determine if the benefits outweigh these potential drawbacks for your specific home.

The best way to ensure the ground next to your home’s foundation drains properly is to divert water away from it as much as possible. While a flood wall can stop water from entering the house, gutters and spouts can help direct rainwater and melting snow away from the foundation. Keep your gutters as clear as possible from dead leaves and other yard debris so they can effectively divert water from your house. Add extenders to the spouts so the water runs out and away from your home, not into the surrounding soil.

The best basement waterproofing method depends on the specific issue causing the water intrusion. For minor problems, simple solutions like installing a properly functioning gutter system to direct runoff away and grading the soil to slope away from your foundation can be effective.

If you have more significant water problems, the solution will need to be more robust:

  • For standing water on the basement floor, a floor drain or a sump pump system may be the best solution.

  • For water pooling around the foundation, installing an exterior French drain can intercept water before it reaches the basement walls.

Other effective waterproofing methods, which can be used depending on your home's specific needs, climate, and soil type, include sealing the interior walls, landscape alteration, installing interior drainage systems, and using a dehumidification system to control moisture levels.

Crawl spaces are the more desirable option overall because they provide additional space for storage and utilities, but they are more expensive to install and maintain. Slab foundations are considered a better option in warmer climates where the depth of the frost line isn’t an issue because they’re more affordable, but crawl spaces are better in areas where the frost line is deep or where flooding can be an issue.

Due to the nature of basements, some level of waterproofing is necessary to prevent water from seeping in and causing damage. Some definitive signs that your basement needs waterproofing measures or needs existing waterproofing measures need to be updated include:

  • Water in your basement, including damp walls or puddles on the floor

  • Mold spots in your basement

  • Musty smells or odors

  • Warped doors or walls

  • Cracks in walls

  • Insect issues, such as cockroaches and termites

The Cos Cob, CT homeowners’ guide to basement waterproofing services

From average costs to expert advice, get all the answers you need to get your job done.