Water in the home is the biggest source of mold problems. Robert Weitz, a certified microbial investigator and principal at RTK Environmental Group, has devised what he calls the four ‘Ds’ to fight mold, a simple way for people to remember what they should do before and after water penetrates their homes or businesses to keep mold damage to a minimum.

Discover: First, it’s imperative to keep water from getting inside your home. Check for leaking roofs and seeping basements, cracked foundations, clogged drains and faulty plumbing. Grade soil away from the foundation, and trim shrubs and trees so they are at least a foot from the home’s siding. Finally, keep gutters free of leaves and debris. Now is the time to do a final gutter cleanup, before winter’s snows come a-calling.

Detect: Hire an environmental testing company to conduct air monitoring and surface samplings to measure the amount of mold in your home and identify your affected areas. (Do-it-yourself kits are notoriously inaccurate, and can’t pinpoint the source of the problem.)

Dry: When water invades, turn on your sump pump if you have one. Use an industrial vacuum to suck up as much standing water as possible as quickly as possible. Once all the standing water has been removed, open all windows and doors and use fans and dehumidifiers to continue the drying process. These items are available for rent at home improvement stores.

Ditch: Throw away any soft goods that got wet and did not dry within 24 hours. If there is any doubt, toss it out. If drywall got wet, remove it, including 12 inches above the wet area. In the future, avoid wall-to-wall carpeting in areas prone to flooding. Instead, use easily washable area rugs.