Rainstorms during the spring and summer are a fact of life, and with them can come the threat of a flooded basement.


Your home is made up of many drainage components that work together to direct water where it is supposed to go – onto city streets and back lanes. Keeping water away from the foundation walls of your house is the most important action you can take to minimize your flood risk. Any of a number of improvements can help, but remember that it’s the whole system working together that gives you the best chance of avoiding a wet basement.

Before a Storm:

  1. Start on your roof. Eavestroughs (also called rain gutters) should be regularly cleaned and checked for leaks, poor connections or sagging. It’s important water from your roof flows easily and quickly to the downspouts. Anything that prevents this from happening should be repaired or replaced.
  2. Downspouts should be checked regularly to make sure there are no leaves or other debris blocking the water’s path. Check also for leaks and poor connections where the downspout is attached to the eavestrough.
  3. Downspout extensions take the water away from the house and the foundation walls. Extensions should be at least 6 feet (1. 8 metres) away from the house. If an extension is not possible, place a concrete splash pad at a sloped angle underneath the downspout. In all cases, directed the water to a street or back lane and not into a neighbour’s yard. In older neighbourhoods, some roof downspouts are connected directly to pipes underground. Seek the advice of a plumber or drainage expert before disconnecting.
  4. Good eavestroughs, downspouts and extensions won’t help much if lot grading is poor. Walk around your home and measure the grade from the wall. This includes under steps and decks. The soil, lawn or other hard surface should slope downward at a continuous grade for a minimum of five feet. The soil at the wall should be at least 4-6 inches higher than the ground five feet away. This positive grade should be checked regularly as ground settles over time.
  5. Window wells are an excellent way of adjusting the grade around basement windows that are low to the ground. Window wells have the added bonus of preventing dirt from rotting window sills. Once the window well is installed, backfill the outside of the well with dirt so the positive grade is the same as the rest of the house.
  6. Concrete cracks on your driveway, sidewalk or patio can let surface water seep back to your foundation walls. These cracks or spaces should be sealed and waterproofed with silicone. As silicone wears down over time, this should be done every 3-5 years.
  7. Look for any basement foundation cracks inside your house. If your basement is finished, check to see if there are any wet or damp areas along the walls or on the edges of the flooring after it rains. If there is, you may need to remove part of the wall or flooring to confirm the water source. Have any cracks you find sealed and waterproofed. that you find.
  8. If you have a backwater valve on your sewer line it will help prevent sewer backup into your basement. Check it at least once a year to make sure the flap is free of debris and is moving freely. Lubricate the hinges of the valve if necessary. If you don’t have a valve in your home, consider having one installed.
  9. Many homes have a sump pump that takes excess groundwater from the bottom of the foundation to the surface. A sump pump should be checked regularly to see if it is working properly. This includes cleaning the intake screen and checking for leaks. You can test a sump pump by taking off the floor cover and pouring water into the sump well. The pump that is working properly should automatically begin running.
  10. The sump pump pipe runs to the surface outside the house. Like downspouts, water from this pipe should be channeled away from the house to a city street or back lane and not into your neighbor’s yard

During a storm:

  1. Avoid using water. During a rainstorm, the pressure on your home and the municipal drainage system increases dramatically, sometimes pushing it to capacity. Washing clothes, taking a shower, running the dishwater and even flushing the toilet adds water to the system that may have nowhere to go but up your floor drain and into your basement. This is particularly true if you have a backwater valve as the valve is designed to close during extreme conditions and keep water from the outside getting in. When this happens, water from the inside also can’t get out.
  2. Get your eavestrough extensions down. A long downspout extension is of no value when it’s propped up against the side of the house. Leave your extensions down all the time or put them down when rain is forecast.
  3. Check the power to the sump pump. If you have a sump pump, double check to see that is plugged in and the breaker is on. More than one homeowner has searched for the cause of a flooded basement only to discover their sump pump lacked the power to perform.