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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

Long Island Basement Waterproofing Video Tutorials & Information

Waterproofing Solutions for High Water Table Areas

Watch the videos below to see ACM Basement Waterproofing in action and hear directly from owner Mark McAlpin on the waterproofing challenges Long Island homes face. From real job walkthroughs to expert insights on drainage and water management, these videos show how we approach every basement, crawl space, and foundation problem we encounter.

Protect Your Home Today

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

This video features a 2018 ACM job at a home near the south shore in Amityville, NY. Before our crew got there, the basement regularly took on several inches of standing water after storms, leaving the space unusable and creating a musty, moldy environment.

South shore homes face some of the toughest waterproofing challenges on Long Island due to proximity to the water, high water tables, and storm surge risk. Watch the video to see the step-by-step process ACM used to manage the water at this property and restore the basement as functional living space.

If your basement floods after every storm, the fix is rarely one product or one quick repair. Schedule a free inspection with ACM to find out what your home actually needs.

The Importance Of Water Management in Long Island

Why Long Island Basements Need Water Management, Not Just Waterproofing
In this video, ACM owner Mark McAlpin explains one of the most important concepts in keeping Long Island basements dry: in many cases, the real solution is not waterproofing in the traditional sense, but water management.

Long Island’s high water table, clay-heavy soils inland, and sandy soils near the coast create water pressure that standard waterproofing methods often cannot handle. Sealing a wall does not address the water pushing through it. Real solutions start with understanding how water moves around your foundation and managing it through proper drainage, sump systems, and grading.

If you are dealing with a wet basement and want a real diagnosis rather than a quick patch, schedule a free inspection with ACM.

Surface Waterproofing in High Water Table Areas

This video features a commercial waterproofing job ACM completed in Suffolk County, NY. Owner Mark McAlpin walks through why a surface trench drain was the right solution for this property and when this type of system makes sense for other Long Island buildings.

In high water table areas like Long Island’s south shore, water often does not just come from below the foundation. It can pool on the surface, run toward the building, and overwhelm traditional drainage. A surface trench drain captures that water before it reaches the foundation and channels it safely away. For some properties, especially those with hardscaping or commercial layouts, it is the most effective solution available.

If your property has surface water issues, ACM can assess whether a trench drain or another drainage solution is the right fit. Schedule a free inspection today.

Long Island’s Top Basement & Crawl Space Waterproofing Expert

Learn about ACM Basement Waterproofing, a certified waterproofing company based in Islip, NY and serving homeowners across Nassau and Suffolk Counties for over 25 years.|

ACM specializes in the full range of waterproofing solutions, including French drains, sump pumps, battery backup systems, ventilation systems, and more. Every job starts with a free on-site inspection and an honest assessment from a Certified Waterproofing Specialist. Our work is guaranteed to stop basement seepage and address water issues at the source, not just the symptoms.

If you are dealing with a wet basement, a damp crawl space, or foundation water issues anywhere on Long Island, schedule your free estimate with ACM today.

Ready to Solve Your Basement Water Problem?

Videos can show you what we do, but every Long Island home is different. The only way to know what your basement, crawl space, or foundation actually needs is an on-site inspection from a Certified Waterproofing Specialist. Schedule your free, no-pressure inspection with ACM today and find out exactly what is causing your water issue and how to fix it for good.

Protect Your Home Today

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