Mold: It's become a problem. Below are videos that may help to inform you of what you should do next. Mold can start to grow within 2 hours so the sooner you get started with the clean up the better. #1 You see mold, you smell mold or a musty smell or maybe just a water leak has you suspicious. #2 Clean up any standing water. #3 Assess situation and decide if a professional is needed. Mold can make you sick and cause mental and physical disabilities.