Take a few minutes to check for any cracks or signs of water leakage on the walls and floor of your basement. If you find a small crack, make a point to check it every few months to make sure it isn't expanding. If you find a water leak or a major crack, contact a basement expert to get it fixed.

Angie's How To Inspect Your Basement
A flooded basement can cost anywhere from $1,500-$10,000 to repair, and sometimes even more! By inspecting your basement once a year and taking a few preventative measures, you can protect your basement and reduce the risk of damage from issues like flooding, mold growth and pest infestation.
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It's harder to detect cracks and leaks in a finished basement because the walls and floor are covered. After it rains, check for wet spots in the carpet, especially in the corners of your basement. Also give your walls a sniff periodically. If you detect a musty smell, you may have mold or mildew behind your walls. If you suspect a larger problem, call a basement professional to inspect further.
Sump pumps remove the water that accumulates around and under basements and crawl spaces by pumping it outside. This is important because if the water isn't removed, pressure builds around the foundation of your house which can lead to a basement flood. You should check your sump pump every six months, and your basement inspection is the perfect time to do this. For details, read: Inspect and Maintain Your Sump Pump.
Since basements are often dark and moist, mold can be a problem. Mold is generally white, black or yellow in color and has a cottony or leathery texture. It also carries a strong, pungent odor that's similar to a dirty, wet sock. For more details on what to look for, read: Mold remodel and remediation.
Look for evidence of a rodent or pest infestation such as squirrels, raccoons or insects. Evidence may include things like gnawed wires, shredded paper nests and dead insects. If you see any evidence, we recommend calling an exterminator to help you figure out how they're getting in, how to get rid of them and evaluate potential damage that they caused.