If there was some water in your basement and you cleaned it up, you would expect the mold to go away shortly after. (Assuming you've also used bleach to clean up the existing mold.) When the mold keeps coming back even though the water is gone, it can be pretty frustrating. But to keep your home healthy and in good shape, it's important to figure out what's causing it so you can take care of it properly. Here's a look at some possible causes.
If you've had a spill or some flooding, water that evaporated into the air after that flooding may still be lingering even though you've cleaned up the liquid water. It's also possible that you simply live in a moist environment. Your flooding triggered the initial mold growth, and then the moisture that's naturally in your air allowed it to perpetuate. As long as there's a lot of moisture in the air, the mold will have enough water to thrive and will keep coming back.
The best way to get rid of this humidity is to purchase a portable dehumidifier. These appliances are about the size of a microwave and can be plugged into a normal outlet. They collect moisture from the air and deposit it in a tub, which you'll have to empty every day or two.
A Leak You Don't Know About
Especially if your flooding was due to a leak, it's possible that the leak was not repaired as well as it needed to be. For example, there may still be a few drops of water escaping from the broken pipe, and this could be enough for the mold to thrive. If the pipe that broke is exposed (and not behind a wall), take a look at it and feel around the seam to make sure it truly is dry. If the pipe that broke is behind a wall, consider having your plumber come back to check and ensure that the leak truly was stopped completely.
Some Building Materials Are Still Moist
If you have drywall, wooden flooring, or any other type of absorbent building material in your basement, there's probably still some moisture in the building material, even though you've cleaned up all of the pooling water. This will evaporate in time, and you can accelerate the process by setting up a dehumidifier as discussed above. This will keep the air drier, which will allow the water to evaporate out of the building materials more quickly.
You may need to remove mold with bleach a few times while you're dealing with any one of these ongoing issues.