Top-rated basement waterproofing pros.

Best basement waterproofing pros near Union, WA

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    Verified basement waterproofing services reviews

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

Avatar for TerraFirma
TerraFirma
4.0(
100
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - RepairBasement Drainage Channels - Install

Serving Union, WA and surrounding areas

Approved

In business since 2005

Free estimates

Warranties offered

"Had huge foundation problems at a project of mine on the waterfront. We used terrafirma to both waterproof the entire basement AND lift the foundation. 10/10 would recommend. extremely communicative, very knowledgeable, and even brought a crew in from Oregon to help us stay on schedule. Oscar and jorge got the job done extremely quickly and Seth was fantastic as my project manager."
A System Design Specialist helping a homeowner
Encapsulating a crawl space
Fleet of vehicles in our Portland, Oregon locatio
Loading up our truck for a piering job
Loading up a truck for a waterproofing job

+33

Response time2 hrs
Response rate100%
79 neighbors recently requested a quote
Avatar for MTU Services LLC
MTU Services LLC
5.0(
5
)
Foundation, Basement or Crawlspace - Waterproofing / EncapsulationBasement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Union, WA and surrounding areas

Approved

In business since 2021

Free estimates

Emergency services offered

"We’ve had a lot of crews in our home for various projects over the years, and I have to say this was one of the most courteous. They worked hard, navigating through our kitchen to access the basement and I really appreciated their efforts. Thank you MTU, we now have safe walls in our cellar and fresh beams to keep the house standing ;)"
Elevator pit waterproofing and sealing
Piers under an existing home
Piers under an existing homes middle wall
Solutions/Answers
Response time1 day
Response rate100%
4 neighbors recently requested a quote
Avatar for Harts Plumbers, Electricians, & HVAC Technicians
Harts Plumbers, Electricians, & HVAC Technicians
4.6(
1,470
)
Basement Drainage Channels - InstallBasement Drainage Channels - Repair

Serving Union, WA and surrounding areas

Approved

Super Service Award Winner

In business since 2013

Emergency services offered

Warranties offered

"This company is so professional and kind. Anthony, the rep who came to do the estimate on a basement kitchen sink and shower installation was so knowledgeable. and patient, My elderly mother has moved in and is making our finished basement her new home, he addressed all her concerns and helped to make some smart choices. Lexi, the phone coordinator was lovely as well."
Prep Area
Waterfall Finished!
Excavation jobs and more!
 install grease trap for commercial kitchen
Delivery of Shoring

+334

40 neighbors recently requested a quote
Recommended by86%of homeowners
Avatar for Pinpoint Construction LLC
Pinpoint Construction LLC
5.0(
7
)
Basement Drainage Channels - Install

Serving Union, WA and surrounding areas

Approved

Super Service Award Winner

In business since 2024

Free estimates

Credit card accepted

"I had a great experience with this team; they were skilled and professional throughout the excavation and grading process. Their attention to detail and reliable service left me feeling confident and fully satisfied, so I would definitely recommend them to anyone needing quality work and exceptional service."
Gravel driveway
Ruts in the driveway which causing the water to run down the driveway?
Well utility trench
Gravel driveway
Driveway work in North Kitsap

+15

Recommended by50%of homeowners
Avatar for BUILDING PERFORMANCE PROS LLC
BUILDING PERFORMANCE PROS LLC
4.5(
8
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Union, WA and surrounding areas

Approved

In business since 2025

Free estimates

Credit card accepted

"The workers were on time. Very efficient. They did a blower door test and found the air leaks and insulated these areas. Blew installation above the garage, cleaned out the crawl space and put new installation there and basement. Found a water leak from my toilet,Thank goodness. Covered everything in the basement and swept and cleaned up after. I would recommend them!"
Response time2 days
9 neighbors recently requested a quote
Avatar for KLC EXCAVATING LLC
KLC EXCAVATING LLC
5.0(
6
)
Basement Drainage Channels - Install

Serving Union, WA and surrounding areas

Approved

Free estimates

Credit card accepted

Offers commercial services

"Great company to work with. He was professional, reliable, and communicated well throughout the project. The work was finished on time, and the quality was better than I expected. I’d definitely recommend him to anyone needing excavation or landscaping work, and I would happily use him again in the future."
Stump Removal
Stump Removal
Stump Removal
Stump Removal
1 neighbors recently requested a quote
Avatar for Diversified Crawlspace Servs
Diversified Crawlspace Servs
3.9(
25
)
Foundation, Basement or Crawlspace - Waterproofing / Encapsulation

Serving Union, WA and surrounding areas

Approved

In business since 1992

Free estimates

Emergency services offered

"We had a foot of water in our crawl space after the snow and 6 in. of rain from the December 2021 storms. I had called several companies to come out to take a look and give quotes. Ethan from diversified was the 3rd quote we received. Ethan explained the issue, explained what they would do to remedy it, and answered all my questions. He sent me the quote which was very resonable. BE SURE TO GET SEVERAL QUOTES. ONE COMPANY QUOTED US DOUBLE OF WHAT WE PAID DIVERSIFIED. They were able to get a team out two days later. The team was on time, professional, and did really good work. We ended up needing a sump pump due to ground water coming up. They applied a mold application and completed the work in a day. I highly recommend these guys and did my research prior to having them do the work. I am very impressed and happy we chose them."
crawlspace drainage
crawlspace drainage
crawlspace drainage
crawlspace drainage
crawlspace drainage

+18

Recommended by60%of homeowners
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Basement Waterproofing FAQs, answered by experts

The best type of basement ventilation system depends on your budget, the moisture in your basement’s air, and the types of windows you have down there. You should consider all of these factors when choosing a ventilation system. However, the most effective method for basement ventilation is an energy recovery ventilator (ERV) or a whole-house ventilation system, which preheats or precools incoming air from the outside while also managing water vapor.

There are several small, inexpensive upgrades you can make to upgrade your basement. Although you still need to adhere to building codes and obtain permits when necessary, you can complete small but mighty tasks like painting the masonry walls and installing entertainment devices to make the space more usable. 

When doing any type of project involving mold, it's important to wear the right protective gear. You'll want an N-95 or KN-95 mask to keep yourself from inhaling mold spores, which can be irritating or trigger an allergic reaction in people with weakened immune systems. You'll also want to wear protective eyewear and gloves to limit your contact with mold.

Signs include persistent dampness, mold or mildew presence, musty odors, and visible water stains. If any of these occur, it is advisable to contact a professional for an inspection.

A crawl space encapsulation isn’t always necessary, but it’s a wise choice, especially if you live in an area that sees a lot of precipitation. Sealing a crawl space not only reduces damage caused by moisture, mold, and pests, but it also increases your home’s value. It can also save you money by reducing energy bills and avoiding costly repairs for structural or foundation damage.

The Union, WA homeowners’ guide to basement waterproofing services

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