Whether you’re working with a buyer or seller, it’s important to guide customers through steps to ensure the foundational soundness of a basement that tends to flood.
Water damage in basement

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Susan Eichner and her husband, Tom Considine, used to dread big rainstorms. The resulting seepage in the basement of their 1890 farmhouse in Highland Park, Ill., was enough to require a Shop-Vac to remove. Finally, after years of frustration, the couple decided to renovate the space and keep it bone dry—forever. “If we’re going to make the basement nicer, we’re also going to make it waterproof,” Eichner says.

About 12 years ago, the couple hired contractors to extend their downspouts, put in drain tiles, and install two sump pumps with a battery backup. (They also own a generator.) Was the $9,000-or-so investment worth it? “Absolutely—for resale and for peace of mind,” Eichner says. “When we sell our house, we can say, ‘We had this waterproofing done, and we’ve never had trouble again.’”

Alas, not all homeowners are proactive about fixing a leaky basement. As a real estate professional, here’s what you need to know about your listing and what to tell a seller or a buyer about water in the basement.

What to Tell a Seller

Consider conducting a prelisting inspection. It may cost your client $300 to $600, but it could well be worth it. “A lot of home inspectors will do what’s called a ‘walk-and-talk,’” says Reuben Saltzman, owner of Structure Tech Home Inspections in Minneapolis and a director of the American Society of Home Inspectors. During a walk-and-talk, inspectors flag all of the major items that would come up during a buyer’s home inspection so that sellers can fix them in advance or disclose them. It also gives sellers an opportunity to find the best professionals up front to correct problems rather than rushing to find anyone who is available—often at a higher cost—after a buyer’s inspection, Saltzman says.

Pay now—or pay more later. Tell your clients to waterproof their basements before listing their properties. “You’re really adding value to the house,” says Roy Spencer, president of Perma-Seal, a Chicago-based company that has waterproofed more than 400,000 homes. “You can command a better dollar at resale. People don’t want to buy a fixer-upper. They’re going to look at some other houses and say, ‘They don’t need that work.’” Home buyers are sure to request a discount because of a wet basement issue. “To me, it’s just a no-brainer,” Saltzman says of the transactional benefit of waterproofing a basement.

Check for cracks. “If you have a poured concrete house and you’re getting seepage in one area, the odds are it’s probably a crack,” Spencer says. Hairline cracks are normal because concrete shrinks as it cures – that is, as it hardens and dries over the first 90 days. Thin, high-strength epoxy sealants that are injected throughout the wall can fix smaller cracks, Spencer says. (They essentially weld the concrete back together.) But breaks more than a quarter-inch wide indicate structural problems that may require foundation repair. “The scary stuff is when we see there’s been so much moisture intrusion, there’s silt coming in,” says inspector Steve Johnson, owner of Beneficial Home Inspection Services in Lake Villa, Ill. “We can even put our fingers in the crack.”

Disclose, disclose, disclose. Encourage your sellers to be honest about the condition of their basements in disclosure forms. If you or your client misrepresent a wet basement as a dry one, buyers can sue you later, says Bill Gassett, a sales associate with RE/MAX Executive Realty in Hopkinton, Mass.  

Don’t assume a wet basement is hopeless or wildly expensive to fix. “There really is no problem that can’t be fixed,” says Spencer, whose company works on more than 150 basements a day. “They’re not all big jobs. A lot of times, we just go in and repair a crack. Every house is different. So many people avoid calling. The estimates are free. It costs you nothing to find out what the problems are.” For those who decide to move forward with repair work, job costs can range from $200 to $20,000, with the average around $3,000, Spencer says.

Do it right—with permits. Rules and enforcement vary from city to city and state to state. Visit or call your municipality, and check its website for instructions. Some places, such as Chicago, make it easy to find permit histories online. “Especially if you’re putting in drain tiles and new pumps, the city is going to want to know where that water is going to,” Spencer says. “If they’re going to invest in this and do the right thing, get it fixed permanently.” Waterproof paint, for example, isn’t helpful with big cracks in the basement’s foundation.

Toss damp rugs. It’s a good way to prevent mold. “If you’ve got carpets down there that have been wet, throw them away,” Saltzman says. “You want to be really certain you have a bone-dry basement before you finish that off.” You don’t want to finish a basement before you waterproof it. Otherwise, you can end up with leaks and mold.

Do not use automatic sprinkling systems that spray against the foundation. And don’t overwater flower beds. “You’re concentrating the water against your home,” Saltzman says.

What to Tell a Buyer

Check out the “grading.” Ideally, the house your buyer is considering purchasing should sit on the highest part of the lawn so surface water runs away from the structure instead of toward it. Sometimes, homeowners add a swale—a shallow channel with sloping sides—to carry water toward storm sewers or into the backyard.

Ask the right questions. In nondisclosure states, such as Massachusetts, sellers don’t need to tell the buyers about water issues in the basement—but sellers must answer truthfully if buyers ask a relevant question, Gassett says.

Pay close attention to “finished” basements. The renovation work may be covering up physical defects. “You may still have an ongoing and active leak you can’t see,” says Johnson. Unfinished basements are easier to visually inspect because cracks and moisture stains will show.

Talk to the inspector about moisture meters. These instruments can detect moisture in wood, dry wall, and carpeting. Variations throughout the basement or house may indicate potential problems. “We’re looking for differences,” Saltzman says. “Why is it higher in the suspect area?” Today, these meters, which can cost anywhere from $50 to $1,000, are “pretty standard,” Saltzman says. Typically, inspectors use them without even being asked. (Some inspectors also use thermal-imaging cameras to scan the house, but they detect temperature differences that may not be caused by moisture.)

Ask about warranties. Perma-Seal gives a lifetime warranty, transferable to new owners, for the life of the structure on many repairs. (Sump pumps and mechanical devices have limited warranties.) “Who wouldn’t be a little more comfortable knowing they’re buying a house and there’s a problem, but it’s been fixed?” Johnson says. Find out if the seller hired contractors who are licensed with the state or who are members of professional associations.

Use more than one certified inspector. “Get multiple people looking at something, rather than just one person who can be trying to sell something that’s not necessary,” Gassett says. Among other things, they can distinguish between a normal crack and a structural crack, says Spencer.

Learn about an area’s “water table.” The level below which water saturates the ground is critical: You don’t want a home that’s essentially floating. That’s why basements are rare in places like Louisiana, where the water is so close to the surface. “If the water table rises, it comes up through the floor,” says Gassett. “When you’re coming out of the winter, and you’ve got frozen ground and snow [and then have] a good rain, you’ve got nowhere for the water to go. It ends up seeping into the house.” This type of house may need underground French drains, filled with gravel.

Don’t assume the basement in a brand-new house is waterproof. You can invest in special new-home construction packages that include the installation of a drainage system around the perimeter, with two sump pumps and a battery backup. (Sump pumps typically cost $350 to $600 apiece, Spencer says.) Without that failsafe, water can build up. “If you lose electricity and you have a sump pump [without a battery backup], the basement could flood,” Gassett says.

Check out the quality of the sump pumps and battery backups. How long can the sump pump operate if the power should go out? “A lot of them won’t even run an hour,” says Johnson. If you live in an area with frequent, longer outages, or if you do not want to run the risk of a battery that fails, consider a generator. (They can cost a few thousand dollars, though.)

Get the sewer line inspected. If it backs up, it can cost $15,000 or $20,000 to replace, Spencer says. So a $225 inspection is well worth it.

Look at doors and windows upstairs. If they’re sticky, it can just be humidity – but it can also be a sign of a structural foundation problem that may trace back to water in the basement, Spencer says. A foundation that’s unsettled or sinking can lead to an uneven house on top of it.

Take care of the gutters. It’s nice—but not necessary—to use gutters with a five-inch diameter instead of a four-inch diameter, Johnson says, because “you want more water to drain away from the home.” Once you’ve bought a house, clean the gutters at least once or twice a year. Look for high-quality leaf guards, which can be expensive but decrease clogging. “I have pictures I can share with you of trees growing out of the roof because there’s so much debris with those gutter-guard systems,” Saltzman says.

Check underground drainage systems. Roots can clog them and wreak havoc. “You can have chipmunks making homes,” Saltzman says.

Look at the roof. Fold a paper in half to make an A-line tent—essentially a simple, traditional roof. Think about how easily water can flow off of it. Newer houses may have complicated lines that lead water to concentrate in a small area, such as two valleys in front of the house, instead of being evenly dispersed, Saltzman says.

Here’s to the lowly basement, now often a place for man caves, flat-screen TVs, wet bars, and ping-pong tables, but once known as a place to store potatoes and carrots and to hide out during storms.