What a Wet Basement Is and How to Deal With It

a storage room in basement of house
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Most basements, by the sheer nature of the fact that they are built into the ground, present the possibility that water can intrude, turning what was once a dry basement into a wet basement. This is because water in the soil can put constant pressure on basement walls. Plus, water follows the path of least resistance inside a home and over time can find its way into a basement.

It's important when buying a house with a basement to check for signs of dampness in the basement. It's better to find out before you buy than afterward, especially since you can't rely on seller disclosures. Why can't you rely on seller disclosures? Because the sellers might not know about it. If the sellers did have knowledge, however, and failed to disclose the water problems in a basement, it could be:

  • Difficult to prove in court
  • Take years to get into court
  • Expensive to sue
  • Very expensive to dry out the basement

This is why you should always, without fail, get an independent home inspection by a qualified and accredited professional.

Signs of a Damp or Wet Basement

  • Water stains along the walls or floor. This could be caused by something simple such as an overflowing laundry tub or it could be a result of water seeping in through basement windows, the walls or the floor.
  • Musty odor or damp smell. Excess moisture in a basement can cause an unmistakable smell.
  • Mold. It could be colored black, brown, yellow or green, and you won't know for certain if it's mold without testing it. Often the northwest corner of a house is known as a "cold corner" and susceptible to developing mold.
  • Efflorescence. This condition produces a white or sometimes grayish ash on the walls. Sometimes it sparkles. Efflorescence is caused by salt deposits left behind by evaporating water.
  • Spalling. When water gets inside the surface of concrete, brick or stone, salt deposits from the water cause the surface to flake away, peel or pop off.
  • A sump pump, sitting quietly in a corner, by the way, is not a decoration. It's a sign that the seller regularly pumps out water or had a dampness problem at one time.

    Potential Causes of a Wet Basement

    • Groundwater. Water can seep through floors and foundations due to freakish heavy rain or seasonal run-off, or it could be constant water seepage.
    • Overflowing gutters. Gutters can overflow because of excessive rainfall, clogging from leaves or debris, improper installation — for example, draining from the second-floor gutters into the first-floor gutters — or sudden thaw from frozen gutters.
    • Not enough gutters. Sometimes homeowners install gutters in one or two locations but not all the way around the house.
    • Downspouts. Water problems can be caused by disconnected downspouts or downspouts that aren't long enough to direct water away from the house.
    • Improper landscaping or grading. This causes water to flow toward the house instead of away from the house.
    • Sprinklers. If sprinklers are aimed toward the house, too much water will accumulate at the foot of the foundation and /or leak through the foundation.
    • Condensation from pipes. Often, in high humidity areas, pipes will form condensation and drip, especially from air conditioner units without a release valve.
    • Water leaks inside the walls. If the interior walls lead directly from the attic to the basement, it can provide a direct channel for water from the roof to seep inside the house.

    Possible Solutions & Options to Dry Out/Fix a Wet Basement

    Redirect the source of water. While this sounds simple, it's often overlooked.

    1. Reconnect disconnected downspouts.
    2. Redirect second-floor gutters to separate downspouts.
    3. Increase downspout efficiencies by attaching extensions designed to move water downhill.
    4. Turn sprinklers away from the house.
    5. Clean out the gutters.
    6. Install flashing on the roof and under window sills.
    7. Regrade the landscaping to slope away from the house.

    Install French drains, either under the slab or around the house, along with a drain tile.

    1. Dig a two-foot hole around the perimeter at least six inches wide.
    2. Attach a waterproofing membrane to the house.
    3. Line with clean rocks.
    4. Lay in a four-inch perforated pipe with the holes up.
    5. Backfill with rocks.
    6. Replace the top layer of soil or sod.

    Install a dehumidifier in the basement and install a sump pump in the basement, which will pump the water to the street or at least 20-feet away from the foundation. Also, tuckpoint the exterior and interior walls.

    1. Clean out old mortar and cracks.
    2. Fill with fresh mortar.
    3. Let dry.
    4. Cure by daily spritzing the joints with water for the first week.

    Install a floor drain and insulate the walls. Waterproofing by painting a sealer on the interior walls doesn't really help much if water is putting pressure on the walls. It will eventually leak through.

    In closing, don't store valuables, photographs, paper documents or anything you care to preserve in a wet basement. Moreover, get an expert's opinion, including an engineer's report, if you can, before you buy a house with a wet basement. It might not be worth the hassle.

    At the time of writing, Elizabeth Weintraub, CalBRE #00697006, is a Broker-Associate at Lyon Real Estate in Sacramento, California.