Posted on Google Linda WeissTrustindex verifies that the original source of the review is Google. 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!Posted on Google rose smithTrustindex verifies that the original source of the review is Google. 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.Posted on Google Craig TodaroTrustindex verifies that the original source of the review is Google. 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.Posted on Google Linda RussoTrustindex verifies that the original source of the review is Google. 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.Posted on Google Maria LacosteTrustindex verifies that the original source of the review is Google. 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.Posted on Google William RothsteinTrustindex verifies that the original source of the review is Google. 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.Posted on Google Links2282Trustindex verifies that the original source of the review is Google. 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.Posted on Google Peter WebbTrustindex verifies that the original source of the review is Google. 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
Posted on Google Linda WeissTrustindex verifies that the original source of the review is Google. 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!Posted on Google rose smithTrustindex verifies that the original source of the review is Google. 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.Posted on Google Craig TodaroTrustindex verifies that the original source of the review is Google. 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.Posted on Google Linda RussoTrustindex verifies that the original source of the review is Google. 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.Posted on Google Maria LacosteTrustindex verifies that the original source of the review is Google. 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.Posted on Google William RothsteinTrustindex verifies that the original source of the review is Google. 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.Posted on Google Links2282Trustindex verifies that the original source of the review is Google. 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.Posted on Google Peter WebbTrustindex verifies that the original source of the review is Google. 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
Basement Water Solutions
We get it—the worst storms always knock out power right when your sump pump needs to work overtime. Your crawl space starts taking on water, and there’s nothing you can do but watch. That’s why battery backup sump pumps have become standard equipment for smart Long Island homeowners.
ACM Basement Waterproofing has been installing these crawl space battery backup systems near me for Long Island homeowners for decades. After watching too many crawl spaces flood during outages, we made backup protection a core part of what we do. No Long Island homeowner should have to choose between a dry crawl space and working electricity—you need both, especially here on Long Island where nor’easters and hurricanes are just part of life.
We make it simple, affordable, and stress-free — with guaranteed results.
A major Long Island storm dumping 3-4 inches of rain means water that has nowhere to go except up through your crawl space floor. Your crawl space sump pump handles this fine until the power cuts out. Then you’re in trouble.
We see the same damage pattern after every big storm that knocks out power:
Last spring we got called to a house in Smithtown, maybe 6 hours after they lost power in a storm. The crawl space had standing water, their HVAC system was partially submerged, and the insulation was hanging down like wet paper. The Long Island homeowner kept saying “I have a sump pump, I thought I was covered.” He was, until the power went out. The cleanup and equipment replacement hit thousands of dollars. A backup pump system would have been significantly cheaper.
The concept is simple—when power fails, a battery-powered pump takes over. Getting it to work reliably for years is where things get complicated. We’ve fixed plenty of crawl space backup systems near me in Long Island that looked good on paper but failed when needed.
Here’s what goes into a system that actually works:
The Battery – You need a real marine deep-cycle battery. Figure on 8-12 hours of runtime during heavy pumping, maybe 24+ hours if it’s just seepage. Smaller batteries work for most crawl spaces, but high water table areas need large battery backup solutions.
Backup Pump – Has to be DC-powered and strong enough for real storms, not drizzle. We install large, reliable pumps because when Long Island gets hit, we’re talking serious water volume. Mount it above your main pump so it only runs when needed.
Charging System – Keeps the battery ready between storms. The good ones have smart charging that won’t cook your battery (seen too many batteries ruined by cheap trickle chargers). It should show you at a glance if the battery’s actually charging.
Alarm System – Makes noise when running on backup. Some Long homeowners dislike the alarm, but that sound has saved more Long Island basements than we can count. You want to know if you’re on battery power so you can check how long the outage might last.
Based on decades of crawl space inspections across Nassau and Suffolk counties, these conditions indicate high risk for power-loss flooding:
Your neighborhood experiences frequent outages. If you lose power more than twice yearly during storms, backup protection is essential. Some areas near the water or with older infrastructure are particularly vulnerable.
Existing water management systems. If your crawl space already has a sump pump, it’s because water intrusion is a known issue. That pump becomes useless without power.
High water table indicators. Persistent dampness during dry periods, efflorescence on foundation walls, or rust on metal components all signal ongoing moisture intrusion that will worsen during storms.
Valuable crawl space contents. Modern homes often have HVAC equipment, electrical panels, and storage in crawl spaces. A single flooding event can destroy equipment worth tens of thousands.
Previous water damage evidence. Stained joists, mineral deposits, or repaired foundation cracks tell you water has been there before—and will return.
ooding during outages.. Here’s what tells us you need backup protection:
Your power goes out every time it storms. There are neighborhoods where we just know the lights are going out—older areas with above-ground lines, anywhere with lots of trees, properties near the water where salt corrodes equipment faster. If you’re resetting clocks more than twice a year after storms, you need backup.
You already have a sump pump. This may seem obvious, but that pump was installed because water gets in your crawl space. No power = no pump = flooded crawl space. It’s that simple.
The crawl space stays damp year-round. In August, when it hasn’t rained for three weeks, go check your crawl space. Still smell musty? See white powder on the walls (that’s efflorescence—minerals from water seepage)? Your floor joists have rust stains? You’ve got groundwater pushing up constantly, not just during storms.
You’ve invested money down there. New furnace, central air, hot water heater—we see $15,000-$20,000 worth of equipment in crawl spaces now. Plus whatever you’re storing. One flood ruins all of it. The backup system costs a fraction of replacing that equipment.
There’s evidence water’s been there before. Dark stains on wood, tide lines on the foundation walls, old repairs someone tried to patch—these are signs water has gotten in before. It’s not a question of if it’ll happen again, just when.
We make it simple, affordable, and stress-free — with guaranteed results.
A backup pump is important, but it won’t save you if the rest of your waterproofing is wrong. We’ve seen backup pumps running constantly because the drainage was installed backwards, or burning out because they’re trying to handle what proper drainage should be managing.
Here’s what actually needs to work together in Long Island crawl space waterproofing near me:
Drainage – Crawl space french drains that follow where water flows, not just the perimeter. Water doesn’t care about straight lines. We put drains where water collects—sometimes that means running diagonal lines or adding collection points in the middle of the crawl space.
Primary sump pump – The 1/3 HP pumps they sell at box stores can’t handle Long Island rain. We use superior Long Island crawl space sump pumps near you that last longer than the discount brands.
Battery backup – Has to match what your main pump can do. No point having a 3,000 GPH primary with a 1,000 GPH backup.
Discharge lines – The pipe that carries water out needs to survive winter. Either bury it below 36 inches or install a freeze relief system. Frozen discharge lines are why half the pumps fail in February.
Get one part wrong and your whole Long Island crawl space waterproofing system will struggle. We see it constantly—great pump, terrible drainage. Perfect drainage, undersized pump. Everything perfect except the discharge line freezes every winter. It all has to work together.
Do we still need backup? Power outages are only half the problem. Crawl space sump pumps fail—usually when working hardest during storms. Switch fails, float sticks, motor burns out. Happens all the time. The battery backup saves you either way. Plus, “reliable” power on Long Island is relative. Ask anyone who went 2 weeks without power after Sandy.
Can you add backup to my existing pump? Usually. If your pump is less than 5 years old and decent quality, we can probably add a backup to your Long Island sump pump. Older pumps or builder-grade junk? Better to start fresh. We’ll look at what you have and give you honest advice.
What battery backup sump pump maintenance am I signing up for? Not much. Check the battery charge light monthly (takes 5 seconds). Clean the battery terminals once a year with baking soda and water. Test it before hurricane season. Replace the battery every 3-5 years depending on use.
Why not just get a generator? Generators are great if you’re home to start them. But storms hit when you’re at work, on vacation, sleeping. By the time you get the generator running, you could have inches of water. Battery backup kicks in automatically—no thinking required. Also, a decent automatic generator system runs $5,000-$10,000 installed. Battery backup is a fraction of that.
We’ve been waterproofing Long Island homes for generations. Family-owned, based right here in Long Island. Not a franchise, not some company from Jersey pretending to know Long Island—we live here, work here, and our own basements flood here when things go wrong.
What makes us different from other Long Island waterproofing companies near me:
Every properly maintained backup system we install in Long Island keeps working through storms, exactly when you need it.
The best time to find Long Island crawl space problems near me is when it’s dry and sunny. We offer free inspections throughout Nassau and Suffolk counties—takes about 45 minutes.
What we’ll do during the inspection:
Look, we know nobody wants to spend money on their crawl space. It’s not like getting a new kitchen where you see it every day. But one flood can cost you $10,000-$20,000 in damages and insurance headaches. A backup system is much cheaper.
Call us or fill out the form online. Spring and fall are our busy seasons, so if you want work done before hurricane season, don’t wait to call us.
We make it simple, affordable, and stress-free — with guaranteed results.
*50% Off Materials Discount applicable to new projects over $10,000
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