New City's 1955–1980 colonials, splits and raised ranches sit on Clarkstown's rolling ground, and a good share of them are in the low spots along the Demarest Kill, the Hackensack headwaters and the small streams that feed Lake DeForest. Block foundations with finished basements are the norm, and the complaint is seasonal: dry most of the year, water along the cove joint and through the block in March and April and after the big fall storms. Many of these houses have an original sump pit that was never connected to a drain, so the pump runs but the floor still gets wet along the walls.
The standard New City fix is an interior perimeter drain tied into a proper sump with a battery backup, with weep holes in the bottom block course and a wall vapor barrier behind the finished walls. Houses on the ridges with poured foundations more often have single leaking cracks that injection solves for a few hundred dollars. Outside, New City's wooded lots and long downspout runs make grading and discharge the first things to check.
Interior drain systems that cut the slab are commonly permitted in the Town of Clarkstown; the contractor applies with the Building Department in New City. Every contractor needs the Rockland County home improvement license and insurance.
What waterproofing costs in New City (2026)
| Job | Typical price |
|---|---|
| Foundation crack injection (epoxy or polyurethane) | $250 – $800 per crack |
| Sump pump installation (pit, pump, discharge) | $1,000 – $3,000 |
| Battery backup sump pump | $400 – $1,500 installed |
| Interior perimeter drain + sump (full basement) | $5,000 – $15,000 |
| Exterior excavation waterproofing | $10,000 – $30,000+ |
| Crawl space encapsulation | $3,000 – $15,000 |
| Grading, downspout extensions, window well covers | $300 – $3,000 |
| Basement waterproofing, typical project | $2,300 – $7,600 (avg. about $5,000) |
Ranges are published 2026 national figures (Angi's and HomeGuide's basement waterproofing cost guides for typical projects, interior French drain and exterior excavation ranges; HomeGuide and Angi sump pump and foundation crack repair pages; crawl space encapsulation figures from HomeGuide), not quotes from this site. Rockland quotes for interior drainage systems typically run in the upper half of national ranges. Details: Rockland waterproofing cost guide.
Services in New City
Basement waterproofing
Interior drainage systems, sump pumps, wall vapor barriers and the outside fixes that stop water before it reaches the wall.
Interior vs. exterior systems →Sump pumps & backups
New pits and pumps, replacements, battery and water-powered backups, check valves and discharge lines that do not freeze.
Pump sizing & backups →Foundation crack repair
Epoxy and polyurethane injection for poured walls, block wall sealing and bowing-wall reinforcement with carbon fiber or anchors.
Which cracks matter →Crawl space encapsulation
Vapor barriers, drainage, sealed vents and dehumidification for the dirt crawl spaces under Rockland's older houses and additions.
What encapsulation involves →How it works
- Tell us about the job. Where and when the water shows up, whether the basement is finished, and whether there is a sump already. Photos help.
- We match you with a local pro. One independent waterproofing contractor, licensed in Rockland County and insured, that serves your town. We do not send your request to five companies.
- Get a free quote. They inspect inside and outside and quote in writing, with linear feet, pump, backup and warranty named. You decide; no fee and no obligation.
New City questions
How much does basement waterproofing cost in New City?
A full interior perimeter drain and sump system for a New City colonial typically runs $5,000 to $15,000 by 2026 figures (HomeGuide, Angi), with the local average for a typical project around $5,000 and up; crack injections $250 to $800 each; a backup pump $400 to $1,500.
My sump pump runs but the floor still gets wet. Why?
The pit is collecting only the water that reaches it; seepage along the cove joint and through block needs a drain under the slab edge to carry it to the pit. That is the interior perimeter system.
Do I need a permit?
Cutting the slab for a drain and sump is commonly permitted work in Clarkstown; the contractor handles it. Grading, downspouts and crack injection are not.
Request a free quote in New City
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