Why Basements Floodand what to do about each cause

Inside causes are the most common: a washing machine hose, a water heater tank, a burst supply pipe, a sump pump that failed, or a leak from a bathroom above. The water is usually clean at first, so carpet and much of the drywall can often be dried. Find and shut the valve for the failed item or the main shutoff, and the flow stops.

These losses are the ones most likely to be covered by a homeowners policy if they were sudden. Keep the failed part if you can.

Storm water and snowmelt that collects around the foundation will find the easiest way in, and in Wheat Ridge that is often a window well. Wells are meant to drain through gravel at the bottom, but leaves, soil and snow clog them. During a downpour the well fills and water seeps around or breaks the window. Water running down a driveway into an attached garage or a basement stairwell is another common route.

Because this water has crossed the yard, it is treated as contaminated. Carpet and pad it soaked are usually discarded. For insurance, surface water is generally considered flood, which needs a flood policy.

When the soil around your house is saturated, water presses against the foundation and the floor. It seeps in at the joint between wall and floor, through cracks and around pipe openings. In Wheat Ridge this is most common in spring, after heavy wet snow melts quickly, and near Clear Creek when it runs high with mountain runoff.

Seepage is usually slow, and cleanup is often manageable, but it comes back each wet season unless drainage is improved: better grading, extended downspouts, an interior drain and sump, or exterior waterproofing. Many insurance policies exclude groundwater seepage altogether.

If water is coming up through the floor drain, a basement shower or the basement toilet, especially if it is dark or smells, the sewer line is backed up. Stop running water in the house immediately, or more will come up. Keep away from the water and call for help; this is a sewage cleanup, with protective equipment and removal of porous materials.

Have a plumber clear and camera-inspect your lateral to find the cause. Sewer backup is often excluded from homeowners insurance unless you have a water backup endorsement.

Clean gutters and extend downspouts several feet from the house. Make sure soil slopes away from the foundation. Clean window wells and check their drains before winter and spring. Test sump pumps each spring. Replace rubber washer hoses and watch the base of the water heater. Know where your main shutoff is. Store important items in plastic bins on shelves rather than cardboard on the floor.

For short answers to related questions, see the quick-answer FAQ, or browse all of our guides.

Homes with a sump pump depend on it to keep groundwater below the floor. Pumps fail because the float sticks, the motor wears out, the discharge line freezes or clogs, or the power goes out during a storm. When that happens, water rises in the pit and spreads across the floor, sometimes within an hour in a wet spring.

Test the pump in early spring by pouring water into the pit. Check that the discharge pipe carries water well away from the foundation and is not frozen. A battery or water-powered backup and a high-water alarm are worth considering. Water from a failed sump is usually treated as clean or gray, depending on how long it sat, but many homeowners policies only cover sump failure with a specific endorsement.

An unfinished basement with a concrete floor and bare walls can take a lot of water and dry out with a mop and a fan. A finished basement cannot. Carpet and pad, drywall, insulation, wood trim, built-in furniture and stored belongings all absorb water and either need careful drying or removal.

If your basement has flooded once, consider rebuilding with materials that tolerate water: tile or vinyl plank flooring, moisture-resistant board at the bottom of walls, plastic baseboard and storage on shelves. The next flood, if it comes, will be much easier to recover from.