Waterproofing work you can request
Basement waterproofing
Finding where water gets in and fixing it for good.
French drains and curtain drains
Interior perimeter drains, plus curtain drains that catch hillside water.
Sump pumps and battery backups
New pits, pump replacements, backups and high-water alarms.
Exterior waterproofing
Excavating, sealing and draining the outside of foundation walls.
Foundation crack repair
Sealing leaking cracks, tie holes and pipe gaps in foundation walls.
Encapsulation and vapor barriers
Sealing crawl spaces and damp basements against ground moisture.
Yard drainage and window wells
Downspouts, regrading, dry wells and window well drains.
Ossining sits on the east bank of the Hudson at the Tappan Zee, the river's widest stretch, and much of the village climbs steeply up from the water. The Sing Sing Kill cuts a ravine through downtown, where the Old Croton Aqueduct crosses it on the stone Double Arch built around 1840. Hills like these shape how water behaves. Rain that falls on the upper streets soaks in and moves downhill through the soil, and the first thing it meets may be the uphill wall of your basement.
That is why so many basements here leak on one side only, or show water along the back wall after every storm while the front stays dry. Houses built into slopes often have a basement that is fully buried on the uphill side and nearly at grade on the downhill side. Add old stone or block foundations in the historic parts of the village, rock ledge close to the surface in many yards, and wet springs, and you have the common recipe for a damp basement.
The good news is that hillside water is often predictable. A contractor who understands slopes will look at where water enters the property, not just where it shows up inside. Sometimes the answer is a curtain drain across the yard above the house. Sometimes it is an interior drain along the uphill wall feeding a sump pump. Sometimes it is simply moving downspouts that empty onto a slope that runs straight back at the foundation.
Send a request and we pass it to a local waterproofing contractor who works in Ossining and the surrounding towns. They visit, look inside and out, and give you a written proposal. Requesting an estimate costs nothing.
Before you hire for basement waterproofing
On sloped lots the cause is often uphill. A contractor who only looks at the basement wall may miss it.
Drains and membranes are priced by linear foot. Line items make bids easy to compare.
A drain or pump moves water somewhere. On a hill, that somewhere matters for you and your neighbors.
Find out what it covers, what voids it, and whether it moves with the house if you sell.
Westchester County licenses home improvement contractors. Ask for the number and confirm it with the Department of Consumer Protection.
How it works
- Send the detailsUse the estimate form: your town, which walls get wet, how soon after rain and if your house sits on a slope.
- We forward itA local waterproofing contractor who works in your area receives your request.
- Site visitThe contractor contacts you, inspects the basement and walks the yard to trace where the water comes from.
- Compare and decideYou get a written proposal and price. Take your time and decide if it is right for you.
Old stone foundations
Houses from the 1800s and early 1900s, found in the older parts of the river villages, were often built on fieldstone or rubble foundations laid with lime mortar. Those walls were never meant to be watertight. Over a century, mortar washes out of the joints and water finds dozens of small paths in. Sealing one spot just moves the leak to the next joint. Stone foundations usually respond best to a drainage approach, often combined with repointing the worst joints, rather than coatings or crack injection.
Ledge rock and perched water
Northern Westchester is hilly and rocky, and some lots have bedrock close to the surface. When rain soaks into the soil and hits rock, it runs along the top of the rock until it finds an opening, which can be the gravel backfill around your foundation. This is why some basements leak even when the yard looks well drained. Rock also makes digging slower and more expensive, so it affects which fix makes sense.
Runoff from above
On a hillside, your basement deals with your own roof water and whatever comes down from the properties and streets above you. Driveways that slope toward a garage, patios that tilt toward the house and lawns that funnel water into a low corner all add up. Ossining's village and town alerts regularly warn about flash flooding and road closures on Route 9A during heavy storms, which tells you how much water moves through this area in a short time.
Dehumidify, then decide
River towns are humid in summer, and cool basements collect condensation. Before paying for drainage, run a dehumidifier for a few weeks and see whether the dampness goes away. If puddles still form after rain, or the walls stay wet behind a foil test patch, you are dealing with water entry and a contractor should look at it.
Typical basement waterproofing costs
National figures from published cost guides. They are not quotes, and northern Westchester prices often sit toward the high end.
| Job | Typical range |
|---|---|
| Interior waterproofing, average project | about $3,000 |
| Exterior waterproofing project | roughly $7,000 or more |
| Interior French drain, per linear foot | about $40 to $100 |
| Sump pump, professional installation | about $1,200 to $2,500 |
| Epoxy injection, per crack | about $800 to $1,500 |
| Excavation, per cubic yard | about $50 to $200 |
| Gutter installation | about $650 to $1,750 |
Rounded national figures from the sources below, not quotes. Your price depends on slope, rock, foundation type, wall length, access and permits.
Sources: This Old House, basement waterproofing cost; Fixr, French drain installation
Towns we take waterproofing requests from
Requests come from Ossining and towns within about 15 miles, from Peekskill and Yorktown down to Tarrytown and Elmsford.
Questions homeowners ask
Why does only one wall of my basement leak?
On a sloped lot, groundwater moves downhill and presses hardest on the uphill wall. Roof water from a nearby downspout can also concentrate on one side. A drain along that wall, or a curtain drain above the house, is a common fix.
How much does basement waterproofing cost in Ossining?
This Old House puts interior waterproofing at about $3,000 on average and exterior work at roughly $7,000 or more. Rock, steep slopes and long walls raise the price. Get at least two written estimates for larger jobs.
Can a stone foundation be waterproofed?
Yes, but usually by managing the water rather than sealing the wall. Interior drainage with a sump pump, plus repointing badly washed-out joints, is a common approach. Coatings alone tend to fail on stone.
What is a curtain drain?
A gravel-filled trench with a perforated pipe, dug across a slope above the house. It intercepts groundwater and surface runoff before they reach the foundation and carries them around the house.
Who will come to look at my basement?
A local basement waterproofing contractor who serves Ossining and nearby towns. They contact you directly and give you their own written price.
Does rock under my yard change the job?
Often. Rock can channel water toward the foundation and makes excavation slower and costlier. It may push the choice toward interior drainage.
Is waterproofing covered by homeowners insurance?
Generally no. Insurance may cover some sudden water damage, but preventing future leaks is usually treated as maintenance. Ask your insurer about your policy.