How to waterproof a basement

How to prevent a wet basement

The words “wet basement” strike fear into the hearts of most homeowners. And for good reason — the American Society of Home Inspectors estimates 60 percent of U.S. homes have wet basements. And not only do they look, smell, and feel unpleasant, they also pose a risk to your home’s value.

Your home's basement might need a little TLC. From water in the basement after a rainstorm to leaky roofs to malfunctioning sump pumps, those rain showers can wreak some serious havoc if you're not proactive.


Ideas for basement waterproofing

Where to start waterproofing with your basement? Ideally, before there’s a problem. Here are some ways you can help to prevent water from entering your basement.

  • Put your snow shovel to work. Most basements get wet when rainwater or melted snow runs toward houses from roofs, yards, and driveways. So, it’s a good idea to move snow away from the foundation of your home. Push accumulated precipitation 3 to 5 feet away from the structure to help protect your basement from snowmelt runoff.
  • Consider a sump pump. An upright (pedestal) or submersible sump pump that’s been properly maintained can be your home’s first line of defense. Inspect and clean any existing pump and test it by pouring water into the pit. The discharge hose should carry the water several feet away from the house to a well-drained area (and make sure to not let the hose freeze!).
  • Check and maintain your downspouts and gutters. A downspout’s job is to carry accumulated water several feet away to a well-drained area. Start by cleaning your gutters and repairing holes in them. Make sure they are firmly attached to the house and that they slope toward downspouts to allow water to fall directly from the roof to the ground. Reconnect any disconnected downspouts, and redirect spouts and gutters as needed.
  • Watch your window wells. Window wells can collect water, causing leaks into the basement. The perimeter of windows should be tightly caulked and sealed to prevent water entry. All entry points need to be inspected, and don’t forget to check for cracks in the wall or floor where water could seep in.
  • Foster the foundation. To prevent basement and garage flooding, build up the soil around your home’s foundation to divert water, first cleaning up old mulch, leaves, and ground covers. According to, the earth around your house should slope at least 6 inches in the first 10 feet. The grading should consist of fill soil with a clay content of 20 to 30 percent, with free-draining soil as backfill underneath. 
  • Check your insulation. If you suspect that water has gotten into the insulation, or you’re having condensation issues in your basement, you may want to consider adding or replacing the current insulation. You may also want to paint your walls with waterproof paint or sealer.
  • Install water-leak detectors. Knowing when a leak has started is half the battle. Many water-leak sensors even connect to your home’s Wi-Fi and include smart water shut-off valves.
  • Use your yard as a sponge. Just getting water away from your house isn’t enough — the true goal is getting the water to soak into the ground. The American Society of Home Inspectors recommends planting a rain garden in your yard to help soak up the extra water. A rain garden collects water from hard surfaces such as rooftops, sidewalks, driveways, and patios. The shallow decline of the garden holds the water, so it can slowly soak back into the ground as the plants, mulch, and soil naturally remove pollutants from the runoff.

Still at risk for a leaky basement?

The Federal Emergency Management Agency (FEMA) shows the top five ways to prevent basement flooding in this quick video:


Sometimes, the water flows where it wants to flow, despite your best efforts to redirect it, so take some precautionary measures:

  • Try not to store valuables or sentimental items such as photographs and important documents in the basement.
  • If you absolutely must put your valuables downstairs, invest in some plastic shelving units and airtight plastic totes. This can help increase the longevity of those items from other factors besides just water and mold.

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