Top-rated basement waterproofing pros.

Best basement waterproofing pros near Ontario, CA

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Top-Rated Basement waterproofing pros in Ontario - Updated Nov 2026

Avatar for Alpha Structural, Inc.
Alpha Structural, Inc.
4.6(
241
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Ontario, CA and surrounding areas

Approved (Corporate)

In business since 1992

Free estimates

Emergency services offered

"Dan was here this morning, showed him where water was leaking in over our slab and ruining the flooring in the master bedroom. He gave me the full range of possible remedies, from installing a eaves gutter on the roofline outside the bedroom to a full (very expensive) sealing of the entire exterior foundation. And actually recommended that we start with the gutter (which I can do myself) and then monitor the area next rainy season and see if that fixes the problem. No pressure to hire them or spend big $$, just good advice. Couldn't have asked for more. Highly recommended- this is real service!"
Basement Addition
Basement Expansion
Caisson Supported Retaining Wall
Cantilevered Deck Design Build
Deck Expansion and Slope Failure with Retaining Wall

+323

Response time10 hrs
Response rate100%
10 neighbors recently requested a quote
Avatar for Western Rooter & Plumbing
Western Rooter & Plumbing
4.8(
172
)
Basement Drainage Channels - Install

Serving Ontario, CA and surrounding areas

Approved

In business since 1981

Free estimates

Emergency services offered

"This is the 5th or 6th time Western Rooter and Plumbing does a plumbing job in my house over past 10 years. They installed softwater tank, replaced waterheater, fixed plumbing, and more. Always excellent"
Ruben installs a new drainage system under a customers home. Working in a crawl space is rough, but we do what is needed.
Backing up? Got roots? Blast those roots out with a Hydro Jetter! We use a wart hog nozzle that combines controlled rotation with a unique 8 jet cutting configuration optimized for removing roots. It’s better with a jetter! Call us! We got this! ??
Sewer Line Camera
No drain clog too big or small, Western Rooter covers them all!
Justin clearing a Kitchen sink back-up after the Memorial holiday.
HALO 5 whole house water filtration system.

+542

Response time12 hrs
Response rate100%
10 neighbors recently requested a quote
Avatar for Groundworks
Groundworks
3.5(
176
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Ontario, CA and surrounding areas

Approved (Corporate)

In business since 1995

Free estimates

Warranties offered

"Their initial price was really high and I declined. But, when they were left with a crew stuck in my area due to a cancelled job, they were really willing to negotiate. The guys were good and did a good job. I'm really happy I had my slab lifted."
Foundation
Foundation
Foundation
Concrete
Concrete

+16

Response time11 hrs
93 neighbors recently requested a quote
Recommended by38%of homeowners
RSF Construction Inc.
1.0(
1
)
Basement Drainage Channels - InstallBasement Drainage Channels - RepairFoundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Ontario, CA and surrounding areas

Approved

In business since 2019

Free estimates

Credit card accepted

RSF Construction Inc. is a leader in providing our customers with the highest quality service in an honest, efficient, and professional way. Our pledge is to create successful relationships with our customers, employees and community by building trust, treating every project with the utmost integrity and exceeding expectations. We look forward to working with you!

Palm Construction, Inc.
5.0(
112
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Ontario, CA and surrounding areas

In business since 2016

Free estimates

Credit card accepted

It can be a daunting task looking for not only the right contractor for your job but also the right contractor for you. We completely understand what you're going through. We know every customer has different desires, different needs and different schedules. We're not only here to turn your ideas into reality but to make it a memorable experience every step of the way. Call us right now, no matter where you are in the planning process.

Recommended by100%of homeowners
Palm Construction, Inc.
5.0(
90
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Ontario, CA and surrounding areas

In business since 2016

Free estimates

Credit card accepted

"We worked with Ali (sales manager) and Tony (project manager), who took the time to design a project that made sense for our property and our budget, made a number of suggestions and recommendations and were never pushy or tried to "sell" us on something. The crew really went above and beyond to provide top quality workmanship and overall we were in very good hands. Highly recommended!"
Recommended by100%of homeowners
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Basement Waterproofing FAQs, answered by experts

In most cases, a crawl space will not dry out on its own unless the moisture comes from an uncommon flood and isn’t expected to be a recurring issue. For most homeowners, moisture problems in the crawl space will only continue to get worse over time, so addressing the underlying problem with gutter systems or a foundation drainage system and setting up a preventative solution like a dehumidifier is necessary.

Crawl space foundation problems can stem from a few different issues, but the most common are moisture and water problems and soil instability. Moisture and water issues are often a result of poor drainage, which can lead to water intrusion and soil expansion and contraction, leaving your foundation under added stress. A few things can cause soil instability, including poor drainage, karst landscapes and resulting sinkholes, and poorly compacted soil during construction.

If you set up a dehumidifier, it will usually dry out your wet crawl space within 12 to 24 hours. Once the space is dry, it’s a good idea to take preventative measures to keep it dry. These include installing a French drain or other exterior foundation drainage system, installing a sump pump in the crawl space, and installing a vapor barrier in addition to leaving the dehumidifier running.

Yes, water and water vapor can seep through cracks in your basement floor, which means you should address all basement floor cracks, even if they don’t indicate structural issues. Sealing settling cracks and shrinkage cracks is a good idea to keep water and moisture outside where it belongs. Doing so can improve your indoor air quality, reduce the risk of mold growth, make your home more comfortable, and help prevent pest infestation.

You should plan on waiting at least a year and ideally two to three years after construction before finishing your basement. This will give the foundation time to settle in response to the weight of your home and the expansion of the surrounding soil. You can then repair your foundation and seal any cracks as needed before finishing it to reduce your risk of future leaks or other issues.

The Ontario, CA homeowners’ guide to basement waterproofing services

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