A flooded basement can be a major disaster, especially if you have a finished basement. Your first priority needs to be dealing with the water inside your house, pumping it out if necessary, cutting power to the basement if the water threatens to rise to the level of your electrical outlets, and getting things dried out so that mold and mildew don't become a problem. In finished basements, you may need to pull up the carpet and replace the carpet pad. But when all of that is done, you still need to take steps to make sure it never happens again. The good news is that, in most cases, doing so is no big deal.

If you've been living in your house for several years or more and this is the first time the basement flooded, then chances are that the flooding is due to a recent problem. A likely culprit is your gutters. If they are clogged and overflowing, or if a broken drainpipe is draining water toward your house, this could cause the flooding. You can test your gutters by spraying water from a hose onto your roof or directly into the gutter. Do this at several locations to make sure that all of your gutters and drainpipes are functioning properly. If they're not, have them cleaned or repaired as needed.

The more likely cause of basement flooding is poor drainage, the result of water from the more elevated parts of your lot draining toward, instead of away from, your home's foundation. If this is the case, you need to install a trench drain (also known as a French drain) to reroute the water.

 

Trench drains are simple, but effective. They consist of a trench--roughly a six inches wide by two feet deep--that is dug alongside your house, about four feet from the foundation, where water drains or collects. The trench should continue to a lower point on your property so that water runs away from your house. The trench is lined with gravel and then perforated 4" PVC pipe is laid in the trench, perforation-side down. The trench is then filled in with more gravel and topped with sod. Installing a French drain is a manageable do-it-yourself project, or you can have a landscaping or irrigation contractor do it.

Ask The Builder, A Simple Trench Drain, by Tim Carter