Top-rated basement waterproofing pros.

Best basement waterproofing pros near Diamond Bar, CA

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Top-Rated Basement waterproofing pros in Diamond Bar - 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 Diamond Bar, CA and surrounding areas

Approved (Corporate)

In business since 1992

Free estimates

Emergency services offered

"Erinn was my initial contact and he gave a very through and fair estimate. We had structural work done to support floor joists and large beams under the garage that needed replacing. Ernesto and his team, Julio, Salvatore and Gilder worked tirelessly to complete the work and were respectful, punctual, informative and good humoured throughout the entire process. I would not hesitate to use them again or recommend them to others. A really great company!!"
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%
12 neighbors recently requested a quote
Avatar for Western Rooter & Plumbing
Western Rooter & Plumbing
4.8(
172
)
Basement Drainage Channels - Install

Serving Diamond Bar, CA and surrounding areas

Approved

In business since 1981

Free estimates

Emergency services offered

"I returned home from a trip and found water all over my downstairs bathroom and adjoining shed. It was late afternoon and I called Western Rooter who agreed to come out first thing the next day, I had a pretty sleepless night. Rene showed up the next day and assessed the situation and started clean up. Tony soon joined him and the two worked all day until after dark and helped me with cleanup and putting things right. They explained to me what they were doing and why along the way. I felt they charged a fair price. I am so grateful for their service and highly recommend Western Rooter."
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 Diamond Bar, CA and surrounding areas

Approved (Corporate)

In business since 1995

Free estimates

Warranties offered

"Roger and his crew of Manuel, Carlos and Josias did everything we asked for and more. Roger answered all of our questions, kept us informed on the status of the project and managed the project extremely well. We definitely made the right decision having Groundworks do our project."
Foundation
Foundation
Foundation
Concrete
Concrete

+16

Response time11 hrs
95 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 Diamond Bar, 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 Diamond Bar, 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 Diamond Bar, 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

Many prevention methods can be used individually or in combination to waterproof your basement. Some of the most common waterproofing methods include:

  • Using dehumidifiers 

  • Silicate concrete sealers

  • Vapor barriers 

  • Baseboard channels 

  • Drain tile systems

  • Waterproofing paint

  • Drainage systems

  • Epoxy injection

  • Interior French drains

  • Exterior excavation and waterproofing

  • Cement waterproofing

  • Weep tiles

  • Liquid membrane

  • Sheet membrane 

  • Yard grading

  • Gutters and downspouts

Water damage always poses a primary risk of mold and mildew, but growth is not guaranteed. Whether mold develops depends on several factors, including the severity of the water damage and how quickly the area is addressed. To prevent mold, you must act fast—ideally within the first 24 hours. The process involves cleaning up all standing water and thoroughly drying the affected area. If the damage is extensive, the cleanup was delayed, or you suspect mold might be present, it is safest to assume it has grown and contact a professional mold inspector or removal expert to assess the situation.

While water in your basement is unlikely to make you sick unless it’s coming from a sewage backup, mold is likely to start to grow in wet areas within 24 hours, and mold can make you sick. According to the Centers for Disease Control and Prevention (CDC), inhaling mold spores can cause allergy symptoms, including runny nose, itchy eyes, difficulty breathing, wheezing, and itchy skin. Individuals with pre-existing respiratory issues like asthma and immunocompromised individuals are at an elevated risk of symptoms when inhaling mold spores.

You should always hire a structural engineer or a professional and licensed foundation repair company for crawl space repair. These professionals will often be able to treat the symptoms of the issue as well as the underlying problem so that you don’t have ongoing damage. They’ll also often take preventative measures to stop the issue from recurring in the future.

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 Diamond Bar, CA homeowners’ guide to basement waterproofing services

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