How To Prevent-Mold-from-Growing-in-Your-Home 1. Controlling Moisture Keep an eye on the humidity levels. Mold grows where there's moisture, so keeping your house dry is one of the most important ways to prevent mold. Install a hygrometer in your home, as this will measure the moisture levels inside. Ideally, you want to keep the humidity level in your house below 60 percent to prevent mold growth....