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Best basement waterproofing pros near Cos Cob, CT

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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

380 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
4 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
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Basement Waterproofing FAQs, answered by experts

The first step to preventing foundation cracks is to repair any current ones. When one crack forms, it becomes more likely that a second crack will follow. A few other tips include performing regular foundation checks, cleaning spouts and gutters, and installing exterior drains if needed. For those living in a hot and arid area, you should water your foundation every other day.

The most cost-effective foundation repair is using masonry patches and sealants to seal foundation cracks and offer some support to prevent further damage. These methods are used to fix minor foundation cracks quickly. However, they’re not suitable as a long-term solution, and they only offer minimal stability. On average, masonry patches and sealants cost $500, but a sealant like an epoxy crack injection can total over $2,000. If you’re handy and only looking for a temporary solution until you contact a local foundation repair contractor for a more permanent one, you can save hundreds by DIYing this repair.

Regular inspections, maintaining proper grading around the foundation, and keeping gutters clear are advisable. Vapor barriers and sealants may need checking for wear after several years.

One handy thing about whole-house dehumidifiers is, once installed, you don’t have to worry about placement or changing the dehumidifier’s position. But if you are using a portable dehumidifier, we suggest keeping it away from walls, vents, and furniture. It needs a central, unobstructed spot with access to lots of air to do its job.

If not properly maintained, an underground downspout may damage your home's foundation. A clogged downspout can back up, causing water to pool around the base of your home and seep into the foundation. Regular inspections and maintenance keep your downspout in good working order, preventing damage and protecting your home.

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.