Top-rated basement waterproofing pros.

Best basement waterproofing pros near Ontario, CA

Enter your zip and get matched with up to 5 pros

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
...
Showing 1-10 of 131
Basement Waterproofing FAQs, answered by experts

The primary reason homes have crawl spaces is so the foundation can reach down below the frost line to avoid dangerous soil movement and structural damage when the ground freezes. They’re more popular in colder climates where the ground freezes down to a few feet, and slabs are most popular in warmer areas where there is no frost line. Crawl spaces also provide a space for utility lines to run where they’re at less of a risk of freezing.

Ideal humidity conditions generally range from 30% to 50%, with 45% considered optimal humidity for most homes. If your humidity levels drop below that range, you can turn your dehumidifier off. Additionally, suppose the temperature where the dehumidifier is installed falls below 60 degrees Fahrenheit. In that case, it's best to turn it off and unplug it since cooler temperatures can cause the unit's coils to freeze.

There are a few downsides to a wet room, the most important of which is the risk of mold growth from the moisture and humidity. Standard bathrooms can have the same issue, but wet rooms are more likely to experience problems because water is less carefully contained. You also have less privacy since the entire bathroom is open, and the room must include waterproofing, which makes wet rooms more expensive to install than regular bathrooms.

You don’t always need to install a dehumidifier in your encapsulated crawl space, but it might be a good idea in certain instances. If you notice obvious signs of condensation, mold, or musty smells permeating from your crawl space, a dehumidifier can help. It’s ideal for homes in humid areas.

In a worst case scenario, structural damage like rust on metal beams, rotting wood, and swelling on doors and windows can signal moisture problems that would benefit from a dehumidifier.

Water damage always poses a primary risk of mold and mildew, but growth is not guaranteed. The chances of mold developing depend on several factors, including the severity of the damage and how quickly the area is cleaned and dried. To prevent mold, you must act quickly—ideally within the first 24 hours. Clean up all water and thoroughly dry the affected area. If the damage is extensive, you were unable to address it immediately, or you suspect mold has already started to grow, it is best to assume it is present and hire a professional mold inspector or removal expert to assess the situation.

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.