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Long Island Chooses Us
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Linda Weiss profile picture
Linda Weiss
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We feel very fortunate to have found this company. I met with Mike regarding leaks in the basement. He assessed the entire house, gave me options and clearly explained the process. Everyone from Mike, to the secretary in the office to the workers were absolutely amazing. They did the work as promised, gave us a reasonable price, and left the place immaculate. We could not be happier with the results! This is a great family owned business. You can’t go wrong!
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rose smith profile picture
rose smith
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The work was done with the utmost professionalism and competence. The service representative was very thorough in examining the dehumidifier, air purifier and sump pump and provided any service needed including draining the pump.
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Craig Todaro profile picture
Craig Todaro
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Mark took it upon himself to come to my home and examine my issue himself. He is knowledgeable not only in basement waterproofing, but also in land grading, excavating and several other adjacent topics. While it was concluded my issue was not foundation oriented, he did not hesitate to propose several other creative ideas to help address my issue. He has a great disposition, and I would not hesitate to recommend his services to others.
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Linda Russo profile picture
Linda Russo
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I bought my house 24 years ago, and for 24 years I lived with water coming in to my finished basement. A few years back I hired another company to put in a French Drain System which never worked. As the storms got worse the water in my basement increased. Because of my previous experience I was hesitant to hire another company until I read about ACM and met Mark who was highly recommended by my Home Service Company. Mark spent about 2 hours explaining the process, and what was needed. In February 2025 ACM put a extensive French Drain System which included taking down the sheet rock walls, demoing tile and placing a membrane along the whole perimeter of the drain system. All of this work was completed in 3 days exactly what Mark said. The guys were professional, polite, and best of all they were careful to save my Radiant Heating System which was under the tile. Since the French Drain System was placed I have not had 1 drop of water coming into my basement. I am very grateful to Mark's ACM Company, and was able to refinish my basement without fear of water damage. I highly recommend ACM Basement Water Proofing to all who are having water problems with their basement.
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Maria Lacoste profile picture
Maria Lacoste
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ACM Basement Waterproofing did an excellent job in my basement, no more water intrusion. The job was handled professionally and on time. I am happy to recommend them.
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William Rothstein profile picture
William Rothstein
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I chose ACM because of their "Best of Long Island" award, and I'm glad I did. Mark's crew (led by Joe) installed an interior French drain and a sump pump in our basement. Six months later, we've had no problems with water. These guys know what they're doing.
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Links2282 profile picture
Links2282
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My wife and I would like to say thank you to Mark and his team for their excellent work installing a French Drain in our finished basement. For years we had to worry about flooding if we got a large amount of rain in a short time. The entire staff was totally professional. knowledgeable, competent and efficient. They were clean and caring and after each day they protected the whole worksite. Without a doubt, we would recommend them for all your basement waterproofing needs.
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Peter Webb profile picture
Peter Webb
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I called acm after finding water in the basement. Mark answered the call and quickly helped diagnose the issue. He guided me to check baseboard and sure enough a broken valve was causing this leak. It's good to find someone to help a homeowner without rushing to take their money. It's good to find a honest business man
Bethpage Best of Long Island Winner warded to ACM Basement waterproofing
Angi Super Service Award for ACM Basement Waterproofing in Long Island
Basement Health Association Star award given to ACM Basement Waterproofing in Long Island

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Basement Water Solutions

Best of Long Island Award for Basement Waterproofing in Long Island
Angi Super Service Award for Basement Waterproofing in Long Island

Why ACM For Your Home

Reliable Basement Waterproofing, Foundation Repair & Crawl Space Waterproofing in Long Island

Choosing a basement waterproofing contractor is a big decision. You are letting strangers into your home to do work that affects your foundation, your basement, and the long-term value of your property. We think you should know exactly who you are hiring and why. 

Protect Your Home Today

We make it simple, affordable, and stress-free — with guaranteed results.

ACM Basement Waterproofing Long Island's experts

What Sets ACM Apart

No other waterproofing company on Long Island can compete with us when it comes to credentials and customer satisfaction. Consider these points:

  • No Mess No dust, no muddy footprints, no mess. We cover the floors with drop cloths and the furniture with plastic. As one satisfied customer said, “You left my basement cleaner than it originally was.”
  • Customer Satisfaction We have tons of references you can call and testimonials you can read from satisfied customers all over Long Island. We have never had a complaint with consumer affairs in either Nassau or Suffolk County.
  • BHA Certified Waterproofing Specialists There are only a handful of BHA Certified Waterproofing Specialists in all of New York State, and ACM is one of them. Certified Waterproofing Specialists are tested experts in hydrogeology, construction, ethics, and safety.
  • Backed by Research Unlike companies that depend on a steady flow of brand-new “patented products,” our systems are not something we made up to make a quick sale. They are designed by industry experts and backed by decades of research.
  • Customized Solutions We do not believe in one-size-fits-all systems. We use a variety of solutions and often combine them to make sure your basement stays dry no matter what.
  • Licensed and Insured We carry full licensing and insurance in both Nassau and Suffolk Counties, so you are protected from the moment our crew arrives until the job is complete.
  • Warranty-Backed Work Every waterproofing system we install is backed by a written warranty. We stand behind our work because we know it lasts.
  • Local and Family-Owned ACM is family-owned and operated, based right here on Long Island. We are not a national chain or a franchise. When you call us, you are calling neighbors.
  • Free, No-Pressure Inspections Every inspection comes with an honest on-the-spot assessment and a clear written estimate. No high-pressure sales tactics and no upselling.

From basement waterproofing to egress window installation, foundation repair to crawl space waterproofing ACM is your trusted Long Island contractor.

Our Owner, Mark McAlpin

Mark McAlpin, owner and expert ACM Basement Waterproofing

Read through our testimonials and you will see the same handful of words over and over: knowledgeable, honest, professional, timely, clean, responsive. You will also see one name come up again and again: Mark.

Mark McAlpin is the owner of ACM, and he is personally involved in nearly every job we do. In most cases, Mark is the one who conducts your inspection, writes up the recommendation, and provides your estimate. That hands-on involvement is rare in this industry, and it is a big part of why ACM has earned the reputation it has.

It is because of Mark’s experience and standards that ACM has become what it is today: the most knowledgeable, qualified, and honest group of waterproofing specialists on Long Island.

What to Expect When You Call

When you call ACM, here is how the process works:

  1. A representative will schedule a free inspection at a time that works for you.
  2. Mark or one of our specialists will visit your home, examine your basement, and ask questions about the issue.
  3. You will get a free, honest, on-the-spot recommendation. If the fix is something you can do yourself, we will tell you that.
  4. If the work calls for a professional, you will receive a clear written estimate with no pressure to commit on the spot.
  5. Once you approve the work, our crew handles everything from start to finish, including cleanup.
Long Island Basement Waterproofing Team Installing System

The ACM Difference

When you hire ACM, you are not just hiring a contractor. You are hiring a family-owned Long Island business with decades of experience, certified specialists, an A+ BBB rating, and a perfect record with consumer affairs in both Nassau and Suffolk Counties. You are hiring the owner himself to walk through your basement. And you are hiring a team that treats your home the way we would treat our own.

Protect Your Home Today

We make it simple, affordable, and stress-free — with guaranteed results.