Tips to Stop a Mold Problem | Kings Cleaning Service, Inc.

Clean up any leaks or spills right away. If moisture is removed within 24-48 hours of appearing, mold is unlikely to grow.
Check your roof and repair or replace it immediately if you detect a leak; also repair any cracks or openings in your siding, and make sure your rain gutters are clear of debris and functioning properly.
Make sure the ground around your home slopes away from the building, not toward it.
Properly insulate your walls; this will help keep condensation from forming on your interior walls.
If you see condensation around windows or on walls or pipes, dry the wet surface and reduce the moisture source. If you have condensation, it could be a sign of high indoor humidity.
Keep indoor humidity low, ideally between 30 and 50 percent. You can find humidity meters at most hardware stores.
Properly vent appliances that produce moisture, including clothes dryers and stoves.
Run a bathroom fan when showering, and a range hood when cooking or running the dishwasher. If you don’t have fans, open windows.