Co-op Board Learns the High Cost of Ignoring Neighbor's Rain Runoff

For years, rain runoff from the townhouse roof next door to our co-op has flooded our backyard and seeped into our basement, taxing our sump pump and creating mold. The neighbor recently moved into an assisted-living facility and sold the townhouse to one of her children. What's the best way for us to approach the new owner and get this problem straightened out?

For years, replies the Ask Real Estate column in The New York Times, you failed to tell the neighbor about the runoff problem. She couldn’t fix a problem she didn’t know existed. Neither can the new owners.

“There is no duty to do anything if you don’t know about it,” says Alan S. Golub, a litigator and principal in the New Jersey office of the law firm FSKS.

Your co-op board needs to put your new neighbors on notice immediately. Introduce yourself and alert them to the problem. Keep the conversation polite, positive and friendly. Ask if they would investigate from their end. They might be able to redirect some of the water, reducing the impact to your property. Putting the conversation in writing is key, so follow up with a letter reiterating the discussion.

Before you can make specific requests, you need more information about your home. Start with the mold. Contact a licensed professional who can assess the extent of the damage and advise you on how to remediate it. Have the house and property evaluated by a waterproofing expert or a civil engineer to determine the source of your water issues and advise a mitigation plan. Contact the city to see if there might be a larger drainage issue in your area that needs to be addressed, like blocked storm drains.

If your neighbor’s runoff is indeed a significant source of the problem, go back a second time and communicate what you’ve learned, and ask them to make the necessary repairs. You could offer to share the cost — not because it’s your responsibility, but because it might help get the job done, and because neighbors sometimes do this for repairs that are mutually beneficial, like taking down a sick tree. 

Because you waited so long to act, you may have weakened any potential legal claims against the neighbor. “You could be stopped from bringing your claim because you sat on your rights without enforcing them,” Golub says.

Regardless, litigation should be an avenue of last resort, as it is costly and will undoubtedly sour your relationship with your new neighbors. In situations like this, waiting for years to act is never a good idea.