Floodproofing Your Home
If your home has plumbing fixtures or floor drains that are below street level, your basement can flood.
Water can enter your house in a number of ways, including:
1) Flooding or rainstorms
2) Sewer backup
3) Groundwater seepage or spring melting
Sometimes there may be no visible water in your basement, but it still might be damp. This page gives tips for preventing moisture from forming, as well as preventing water from entering your basement. For information on protection from major floods, see Flood Safety.
Flood Proofing Maintenance
These simple steps will help to prevent water from entering your basement and will help to keep moisture forming:
- Make sure that internal moisture sources such as clothes dryers and bathrooms are vented outside
- Use humidifiers and dehumidifiers carefully. Put humidifiers on a higher level than the basement. A dehumidifier in a moist basement may actually draw moisture into the basement.
- If your basement is moist, don't open the basement windows in the summer
- Make sure your basement drains are clear of roots, grease, etc. Have your sanitary service cleaned out at least every other year. Your sanitary service is a pipe that carries discharged water from toilets, sinks, showers and disposals from the house to the sanitary sewer in the street. A slow drain might indicate that more frequent cleanings are needed.
- Clean out gutters and downspouts. Make sure downspouts extend at least four feet from the outside wall of the house.
- Shape the soil around your foundation to help water drain away from the building
- Check for cracks in the foundation, chimney, and fireplace. If you find cracks, consult an expert.
Preventive and Corrective Measures
Start with the simpler and less expensive measures:
- Build up the ground around your foundation so that it slopes away from the house at a slope of at least one inch per foot, for at least six feet
- Put appliances, furniture and other items in your basement up on blocks
- In window wells, place about 1/2 inch of coarse gravel sloping away from the house. Make sure that the sides of the window well extend above ground level. Cover the window wells – available at most home improvement stores.
- If the heating ducts are under the basement floor, make sure they are insulated and watertight
- If only three or four inches of water are present, install a float plug in the drain. A float plug is inexpensive and easy to install, and does not require a permit. If the floor drain pipe backs up, the float rises and plugs the drain. However, the plug must be removed to drain any water from the basement and it can cause problems if there is more than 4 inches of water in the basement.
- Have a licensed plumber install a backflow valve to keep water from backing up into your basement through the drain
- Install a vapor barrier or retarder on the basement walls. Please note a building permit may be required.
- Install a false floor over the basement floor, allowing the water to flow to a drain or sump pump
- Install an interior or exterior drainage system, including a sump pump. An exterior drainage system is the most effective, but may also be the most expensive. This must drain to the surface on the property (a permit is required).
For more information about protection from flooding, see these sites:
- North Dakota Extension Services offers information about Coping with Floods
- FEMA provides information about protecting your propery from flooding here: Install Sewer Backflow Valves
Disclaimer: The items listed on this page are merely summaries of the possible measures that can be used for floodproofing your home. For more information and specific how-to steps, consult with experts and check the websites listed.
Last updated Feb. 1, 2012