Lowe's Home Improvement

Detect and Prevent Water Damage and Mold

Water damage is costly and may occur before you notice trouble. Mold can create health concerns. Learn what to look for and how to prevent problems from water leaks.

Check Water Sources to Help Prevent Mold and Water Damage.

Water and Mold Problems

Water Meter.

Standing water on the floor is easy to see. Less obvious signs of problems include:

  • Unexpected increases in your water bill
  • Stains on walls, floors or ceilings
  • Damaged or warped flooring
  • Warped bottom panels in under-sink cabinets
  • Peeling paint or wallpaper
  • Corrosion on plumbing valves and fittings

Deal with problems as you find them. Clean up any water or moisture, locate the source and make repairs. Tracking down a leak isn't always straightforward — water can travel along components in the building structure, so the indications of the leak may be in a different part of the home than the leak itself. If necessary, contact a professional roofing contractor, plumber or water damage restoration specialist to help with identification and repair.

In addition to the damage that water causes, it can encourage the growth of mold on walls and floors — where it's readily visible — and in ductwork, attics and crawl spaces — where you might not notice it. A musty odor is a sign that mold may be present.

Mold can cause damage and lead to health problems — deal with it quickly. If the affected area is larger than 3 feet by 3 feet, the Environmental Protection Agency recommends you find a professional mold remediation contractor. For smaller areas, you can clean nonporous surfaces with commercial cleaning products, soap and water or a solution of a cup of bleach to each gallon of water. Follow the instructions and safety precautions for the cleaning product you use and wear appropriate safety gear. Porous surfaces such as drywall need to be replaced. For more information on mold in the home and how to clean it up, see A Brief Guide to Mold, Moisture, and Your Home on the EPA's web site.

Inspecting common sources of water leaks and taking some simple preventative measures can be an effective way to reduce the risk of water damage and mold.


Several molds, such as Stachybotrys — more commonly known as black mold — can be hazardous. If you have concerns about dealing with mold yourself, contact a professional.

Good to Know

A toilet that runs when not in use may not leak water onto the floor, but it wastes water and needs to be repaired. See Test a Toilet for Leaks for tips on correcting the problem.


Bathroom with Sink, Toilet and Tub.
  • Every 6 to 12 months, inspect water lines, shut-off valves and fittings for fixtures such as sinks, toilets and tubs and for appliances such as washing machines, dishwashers and ice makers. Check for cracks, loose connections, kinks and corrosion. If you find a leak, turn off the water to the fixture or appliance until you can make repairs.
  • Check around toilets to make sure water is not leaking at the base — an indication that the wax ring between the toilet and floor might need replacing or that there might be a crack in the base.
  • If the temperature drops near the 20°F mark, allow faucets connected to vulnerable pipes — those not protected in insulated spaces — to drip. This helps minimize the risk of burst pipes by relieving pressure if the pipes freeze. See Frozen Pipes: Prevention and Repair for more ideas.


  • Replace washing machine supply hoses at least every five years. Consider using stainless-steel mesh hoses. Keep the machine properly balanced — over time, an unbalanced machine can move, pulling free the hose connections. Read Maintain Your Washer and Dryer for instructions on replacing hoses and balancing the washing machine.
  • Consider turning off the water to the washing machine when it's not in use.
  • Don't operate a dishwasher or washing machine while your house is unoccupied.
  • Follow the manufacturer-specified maintenance for your appliances, including your water heater. Have the water heater inspected every couple of years. 

Roof and Gutters

Roof and Guttes.
  • Have your roof inspected every three years by a professional, but also check routinely for damage you can see from the ground — such as broken and missing shingles or damaged flashing. A poorly maintained roof can lead to leaks in the home and additional damage to the roof itself.
  • If your roof doesn't have a drip edge or drip cap, consider having one added. This component helps keep water away from the roof deck and directs runoff into gutters.
  • Keep gutters clear and well-maintained. Gutters that overflow, leak or don't drain properly allow water to seep into your roof and into your foundation, crawlspace or basement. See Gutter Cleaning and Repair for steps to keep your gutters working correctly.
  • Make sure gutter downspouts direct rainwater away from the home's foundation. Use extensions to carry water at least 6 feet from the house.

Exterior Walls and Foundation

  • Inspect the exterior of your home. Caulk around gaps at plumbing and ventilation entry and exit points. See How to Caulk for instructions. Repair cracked mortar joints.
  • Check to see if roots from shrubs near your home have caused damage that can allow water to enter the foundation. You may need to remove shrubs that are close to the house to prevent problems. Roots can also damage and block in-ground pipes, causing leaks near the foundation and sewer backups in the home.
  • Keep shrubbery beds and other landscape features sloped to direct water away from the home.
  • Look for evidence of erosion or settling at the foundation that can indicate water problems.

Additional Tips to Avoid Water Damage

  • Have your attic ventilation and insulation inspected annually and seal gaps that allow warm air into the attic — such as those around access doors and light fixtures. When warm air collects in the attic, it can lead to the formation of an ice dam — ice around the eaves that causes water from melting snow and ice to back up under the shingles and leak into your home.
  • If you have a sump pump, test it several times during the year. Follow the manufacturer's maintenance instructions.
  • Check your water pressure with a pressure gauge; typically these screw onto a hose bib. The pressure in an average home is around 50 to 70 pounds per square inch (psi). Higher pressure causes extra stress on pipes and fittings and can lead to leaks.
  • Inspect tile and grout around showers and tubs. Make any necessary repairs. Read Replace a Broken Ceramic Tile and Repair Tile Grout for step-by-step instructions. 
  • Check for leaks around windows during rains and seal any you find.
  • Use exhaust fans in the kitchen and bathroom to move excess moisture out of the house. Moisture in the air can condense on cool surfaces and cause problems. Read Controlling Moisture and Humidity in the Home for more ways to reduce indoor moisture.
  • Locate your water shut-off valve so you can quickly turn off water to the home in an emergency. See Shut Off Your Home Water Supply for instructions on locating the valve.