Signs of a Possible Basement Leak Before Buying a House

basement-leakingBuying a home is a huge decision, and you want make sure your home is a good investment not a money-pit. According to The American Society of Home Inspectors over 60 percent of basements in existing homes have a moisture problem. There are certain indicators to look for that may be clues that there is dampness in a basement. Clues are just indicators so they are not definite and could be misleading. Mildew, mold and rust can all be due to moisture penetrating the basement, but they can also be due to summer’s hot and humid air coming into contact with the cool basement walls.

The truth is that signs of water seepage just indicate that moisture or water has, at some time in the past, seeped into a basement. These signs do not tell you how often this has happened or the extent of the basement leak problem. However they may definitely call for caution, and definitely the need for a professional home inspection.

These are some signs of water seepage:

Mold, Mildew, Damage on Finishes, Water Stains, etc.

In addition to these, other signs of moisture seepage are if cardboard boxes on the floor are sagging, floor tiles are lifting, plaster or drywall is crumbling, peeling paint, there are discolored or rotted wood items near or on the floor, and/or crumbling concrete.



If you notice the nails in the baseboards or wall paneling are rusty, or if the metal electrical boxes have rust on them or rust has started appearing on the feet of appliances, you may very well have a wet or moist basement on your hands.


This is a whitish colored mineral deposit frequently observed on the inside of foundation walls. When water has seeped through the basement walls and evaporates it leaves mineral deposits behind. People often assume that the more efflorescence you have, the bigger problem you have. But the truth is that the drier the air is in the basement, the faster moisture evaporates and this leads to more mineral deposits. If  a dehumidifier was used in a basement you will see more efflorescence appearing. Efflorescence on a basement walls does indicate moisture has seeped in, but it doesn’t tell you how severe the problem is or whether this is actively happening right now.

Repaired Walls

If you see signs that the basement walls have been repaired, either interior or exterior, this suggests that there have been problems with the basement being wet in the past. Look for areas of patching using bituminous “black tar” materials or products, cement patching, or any number of waterproofing products.

Remember, clues are not conclusive. They are only indicators of a leaking basement but can be misleading. If you do see indications of water seepage on a home you are buying during your home inspection, speak to the homeowner about these clues before hiring a contractor to waterproof the house, as the water seepage problem could have already been solved. If the homeowner put in buried drain pipes or solved the water seepage problem by coating or sealing the outside of the foundation wall, you would not be able to actually see the correction.

When you first identify a problem with a wet basement, you should first determine that the source of the water is not from inside the house. A plumbing leak connected to a washing machine, water heater or a malfunctioning cooling system can all be mistaken for basement leakage. And during the hot summer months, condensation can occur on cold water pipes and on the cool foundation walls. These too can be mistaken for water seepage.

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