NJM Safety Center - Residential

Reduce Basement Flood Risks

Follow these steps to reduce the risk of repeated flooding.

Step 1: Evaluate the risk

Does the basement flood every year at approximately the same time? Does the basement flood during random intervals? Where is the basement flooding?

  • Is it at the top of the basement wall?
  • At the bottom of the wall?
  • Through a floor drain?

Step 2: Inspect the location where water is entering and consider these solutions

  • Extend and redirect the downspouts.
  • Reshape the landscaping around the foundation of the building.
  • Caulk any cracks on the interior of the wall around where the water is entering.
  • If the entire wall is damp or water is entering through multiple wall surfaces, this may be a sign of a faulty or missing exterior waterproofing membrane.
  • Consider hiring a licensed contractor to install a waterproofing membrane.
  • For an unfinished basement, consider applying an internal sealant that can be painted on interior surface of basement walls. Frequently, these products require constant maintenance or they will stop working.
  • If water is entering near the top of the wall in one location, an improperly sloped landscape angled toward the building could be the cause.

Step 3: Other location-based solutions

If the water appears to be entering the building near the foundation or through a floor drain: Install a "French Drainage" system around the perimeter of the building or at least in areas subject to frequent flooding.

  • Consider hiring a licensed contractor to install the French Drain.
  • Ensure that the drain has a method for diverting the water away from the foundation. The drain should empty into the primary storm drainage system, a retention pond or other appropriate location.

Install a sump pump with a battery backup system:

  • This may require demolition of a portion of the basement floor to install the pump.
  • To be effective, the sump pump needs to be away from the basement walls and have positive drainage away from the building.
  • Sump pumps should be tested at least once a year, preferably in the early spring, prior to the "wet season".
  • Test the system if a storm is approaching, and make sure the sump pit does not contain any debris that will clog the sump's inlet pipe.
  • Ensure the outlet pipe is clear and the water flows freely to the designated area.
  • If the sump does not operate properly, check the power source for the pump.
  • If you cannot determine the problem yourself, contact a professional to diagnose the problem.

Article provided by the Insurance Institute for Business & Home Safety.