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Help! My Basement Leaks When It Rains

Water coming into your basement during or after heavy rain is a cause for concern. Learn why water leaks or seeps into basements and how to fix the problem.

Basement with a leak and water on the floor

Puddles of water on the floor, stains on the walls as well as musty odors are typical symptoms of basement water leaks or seepage.

Spring rain is great for your flowers and garden, but not so great if all that water is entering your basement. If you notice water in the basement after heavy rain, you're not alone. Water coming up through the basement floor or leaking from a crack in a basement wall are typical symptoms of basement leaks or seepage. This guide will explain what causes basement water leaks or seepage, how to stop water from leaking or seeping into the basement, and how to keep the basement dry. Such solutions include quick DIY options and long-term repairs that require the help of a professional basement waterproofing contractor.

Causes of basement leaks

Basement window and foundation

Water that drains toward the foundation is the primary source of basement leaks or seepage.

The most common cause of basement water problems is the pressure created by the water in the soil surrounding the foundation. The loose soil around your foundation tends to absorb more water. The area around the home is often flooded with rainwater from clogged gutters or downspouts that are discharging water right next to the foundation. Understanding why basement leaks can help you when deciding on the best ways to fix your basement water leaks or seepage. Here are the four primary causes of basement water issues:

  • The "clay bowl effect" is a primary cause of basement leaks. When a foundation is dug for a house, the soil is excavated, creating a bowl-shaped area where the foundation sits. Some of this soil, called backfill, is put back after the foundation is constructed. The backfill soil absorbs more water than the untouched hard-packed soil. When it rains, water collects around the foundation and the loose soil becomes saturated. The water can enter the home through cracks in poured foundations, between blocks, or through the porous concrete. The "clay bowl effect" is especially common in regions that have soils with high clay content (hence the name).
  • When water builds up in the soil around the foundation, the excess water, and the denser soil puts pressure on the foundation. The pressure from the water, referred to as hydrostatic pressure, can push moisture and water through the basement walls and floor. When the soil expands, it creates lateral (or sideways) pressure against the foundation. This can cause damage to your home's foundation and create leaks in the basement.
  • Window wells can be another cause of water leaks in the basement. If a window well is not properly installed or if the drain becomes clogged, the window well can fill with water. During heavy rain, the water can seep into your basement. Water stains on the walls are a sure sign of leaky basement windows.

Water leaking vs. seeping into the basement: What's the difference and how can you identify which problem you have?

Leakage and seepage are two primary causes of wet basements. Although these terms both refer to the movement of water, there are key differences between seepage and leakage in basements. Seepage is the movement of water through a porous material. If there's water coming up through the basement floor, the cause may be water seepage. Leakage is the flow of water through an opening. Basement leaks may occur from a broken pipe or a crack in the foundation.

There are a few symptoms that can help you determine whether you've got a basement leak or seepage issue.

  • Signs of basement water leaks: One of the surest ways to identify a leak is to check for cracks in a concrete wall or between blocks and look for signs of wetness on the wall itself or on the floor below the crack. Basement windows are another typical source of leakage, so look for signs of water intrusion below any windows.
  • Signs of water seeping into the basement: The primary sign of water seepage is efflorescence or white stains on the basement floor or walls, caused by salt deposits from the presence of water or moisture.

Basement leaks and seepage can both contribute to mold growth, musty odors, damage to furniture or items stored in the basement, and other serious water damage. Most signs of basement water damage are obvious, like a puddle on your basement floor or musty odors. But other symptoms can be hard to spot, such as mold growth or rot that’s hidden behind drywall or flooring in a finished basement. Whether there's water leaking in your basement or water seeping into the basement, you’ll likely need to take some measures to protect your home from further damage.

When to do when your basement leaks

If you've got standing water in the basement, the first step is to quickly remove the water to avoid mold and moisture damage. Then take steps to prevent water from getting into the basement, ideally before the next heavy rain. Here's what you need to know and steps to take if water is leaking or seeping through the foundation, and the best ways to fix the problem. If you're still unsure about what to do about water in the basement, a professional basement waterproofer can evaluate the situation and recommend a long-term solution.

  1. Check where water is coming into the basement

    Basement wall crack and wall stains

    Stains along a crack in the basement wall are a sign of a foundation leak.

    If you've got water leaking or seeping into the basement, this situation is a cause for concern. Here are the typical areas of the basement where water can get in.

    • Through cracks in the walls or floor
    • Through the porous concrete foundation
    • At the joint where the poured concrete floor meets the wall
    • Through cracks in mortar joints of block or masonry foundation walls

    Drainage issues around a home’s foundation, including poor grading, overflowing gutters, short downspouts, or clogged window wells can all cause water to pool near the foundation. Foundation cracks and porous concrete, combined with hydrostatic pressure contribute to basement leaks. Fortunately, many leakage problems can be fixed with quick improvements, while more serious basement water problems require installing an interior waterproofing system.

  2. Fix grading to stop water from pooling around the foundation

    Check the slope of the ground around your house. The soil should gradually slope away from the foundation, toward the yard. The goal of yard grading is to create proper drainage to prevent water buildup around the foundation. To fix or improve the grading, add soil around the foundation to create the proper slope. Depending on how big the house is, this could be a time-consuming project, so consider consulting with a landscaper if you don’t have the capacity (or desire) to do it yourself.

  3. Check gutters and downspouts for clogs and leaks

    When it rains, clogged gutters can overflow and rainwater can pool around your foundation. To help prevent the soil around the foundation from becoming saturated, remove leaves and debris from the gutters and downspouts, install gutter guards to keep the gutters clear, and add downspout extensions to direct water away from the house. Consider having seamless gutters installed to avoid leaks, a common problem with standard gutters that have joints.

  4. Clean and cover window wells

    Leaves and other debris can cause window wells to clog and fill up with water. This water can easily leak around the windows and into the basement. Install a fitted window well cover to protect basement window wells.

  5. Seal cracks in the foundation

    Cracks in the foundation walls or basement floor can allow water from the ground outside to leak into the basement, especially after heavy rain when the hydrostatic pressure is greater. An interior sealant might be enough to fix basement wall leaks if the cracks are small and leakage is minimal. If there’s severe cracking or water is still getting into the basement despite previous sealing, consider installing an interior drainage system.

  6. Fix a wet basement with an interior waterproofing system

    Extending the downspouts or sealing basement wall cracks may be effective in stopping water leaks or seepage, especially the first time it happens. If you've got recurring basement water leaks or seepage problems, a basement waterproofing system, including a drainage pipe and sump pump, is the most effective way to prevent problems caused by a wet basement. Here's a video that explains what a waterproofing system is and how basement waterproofing can keep your basement dry.

    Basement waterproofing system with sump pump

    Long-term waterproofing involves installing a quality basement sump pump and drainage system.

    While waterproofing the foundation from the outside is an option, it's typically more expensive and isn't always possible depending on the way the home was originally built. An interior drainage system is a popular long-term solution that reduces hydrostatic pressure, the primary cause of wet basements. Drain tile is installed along the joint where the floor meets the wall - where most water leakage occurs. Water that enters through the foundation is captured by the drainage tile and carried to a sump pump that pumps the water out of the basement. The patented WaterGuard® drainage system uses a unique, patented design that prevents the system from becoming clogged - a common problem with other foundation drainage systems on the market.

Don't ignore a leaky basement

While it's common to have some water in the basement after a hurricane or unusually heavy rain, even a small amount of water in the basement after is a situation that shouldn't be ignored. A wet basement can lead to wood rot, mold and mildew, and serious water and moisture damage. Take steps to fix basement leaks, stop water from seeping into the basement, and dry the basement for good. Schedule a free basement waterproofing estimate from your local waterproofing contractor in the Basement Systems network today.

Updated: September 1, 2022

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