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Preventing Flooding Around Your Home

Rain Barrel Flood PreventionThere are a number of steps you can take around your property to reduce the impact of storm water and even reduce the chances of floodwater from entering your home.

Rain Barrels:
Rain barrels collect rain from your roof. It is free water that you can use in the summer months around your yard. It also helps keep the ground around your home from getting over-saturated.

Storm Drains:
Take time to clean out the storm drains along your street. Keep sticks, lawn clippings, leaves and other debris away from creeks. Take advantage of yard waste collection services offered in your community.

Depression Gardening:
When possible, use the lowest point on your property for planting a garden. Let gravity help you keep your garden green.

Floodwalls:
If your home is not in the regulatory floodway, an innovative technique for safeguarding your home against the onslaught of floodwaters is the floodwall. Experts recommend that the floodwall not exceed two feet in height; it could however be incorporated into a standard chain-link or wooden fence. The floodwall forms a perimeter around the property of a house to divert water away from the property.

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Pumping Out a Flooded Basement

If your basement is flooded, don’t rush to pump it out. Water in the ground outside your house is pushing against the outside of your basement walls, and the water inside is pushing right back. If you drain your basement Flooded Basementtoo quickly, the pressure outside the walls will be greater than the pressure inside, which may cause the basement floor and walls to crack and collapse.

How to Safely Pump Water Out of Your Basement:

  • Never go into a flooded basement unless you know the electricity is off.
  • For insurance purposes, take pictures of your basement before beginning any work.
  • When the water is no longer covering the ground around the perimeter of your house, you can begin pumping the water from your basement.
    • CAUTION: Do not use gasoline-powered pumps or generators indoors as
      they produce deadly carbon monoxide exhaust fumes.
  • Pump the water level down 2 to 3 feet, mark the water level, and wait overnight.
  • Check the water level the next day. If the water went back up and covered your mark, it is too early to drain your basement.
  • Wait another 24 hours. Pump the water down 2 to 3 feet again, and check the water level the next day.
  • When the water stops rising, pump the level down another 2 to 3 feet and wait overnight. Repeat the above steps until all the water is pumped out of the basement.

What to Do After Draining Your Basement:

  • Shovel out as much mud as you can as quickly as possible. The mud left behind by floodwaters poses a health hazard, and it is a lot easier to remove before it dries out.
  • Hose off the walls and floors with clean water and then disinfect them with a solution of 1 ½ cups of liquid chlorine bleach to a gallon of fresh water.
    • CAUTION: NEVER mix bleach and ammonia cleaning products. This will produce deadly chlorine gas!
  • Remove the vents or registers of heating and air conditioning ducts, the wall covers for wall switches and outlets that were flooded. Clean and disinfect them as above.
  • All flexible ducting, including dryer connections, must be replaced for health protection.
  • Check your water system, including drains and utility connections, for leaks, breaks, and loose fittings.
  • Have your water supply checked for any contamination. This service may be provided by your local health department.
  • Before turning on the electricity, check your incoming electrical service for any damage. Replace any wiring, switches and/or outlets that were submerged or got wet during the flood. This may require the services of a professional.
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Cleaning Up and Drying Out Your Home

If your house or its understructure have been under water from recent flooding, you will need to take important steps to clean out bacteria and mold and to dry the building out thoroughly.

Steps for Drying Out the House:

    • Turn off the main power.
    • Open up the house to allow moist air to escape.
    • Remove all wet furniture, contents and carpets or rugs. If you decide to keep some  of these items they must be cleaned and disinfected.
    • Discard all contaminated food products. For more information see our Food Safety page.

Interior Walls:

Interior plaster walls will need to be drained if they are still holding water. Remove the baseboard trim and drill holes about 2" above the floor to let the water out. The holes can be hidden behind the reinstalled baseboards. Flood soaked sections of wallboard will usually have to be removed and thrown away. Paneled walls can usually be dried out by prying out the bottom corner of the paneling and propping it out away from the wall studs.

Exterior Walls:

Insulation in exterior walls will hold moisture and bacteria. It is important to remove any flood soaked insulation as soon as possible so the other building materials can dry out properly. Batt insulation and blown-in insulation cannot be reused in your repairs and must be thrown away. Rigid foam insulation can be removed and disinfected. Once it is completely dry it can be reinstalled in the wall cavity. Once the insulation is removed the wall must be disinfected and thoroughly dried. Dehumidifiers and portable heaters can speed this process up.

Floor Framing:Cleaning Supplies

If the flood waters got into your floor framing but not into your house you will need to check for wet floor insulation. Wet floor insulation must be removed and the framing disinfected and dried out in the same manner as the walls.

Disinfecting:

Disinfect all surfaces that were soaked by flood waters with "disinfecting" or "sanitizing" products. An alternative is to use a mixture of 1/4 cup liquid chlorine bleach mixed into one gallon of water. Remove mildew using household mildew removers or fungicides.

CAUTION: NEVER mix bleach and ammonia cleaning products. This will produce deadly chlorine gas!

Reconstruction:

Reconstruction materials should be water resistant so instead of regular wallboard or plaster, use water resistant or waterproof wallboard for interior wall surfaces. Install wallboard horizontally. Some additional tips:

  • Use rigid foam insulation instead of batt or blown-in insulation.
  • Use galvanized or stainless steel hardware.
  • Use indoor-outdoor carpeting.
  • Use exterior grade plywood for sub-floor reconstruction.

 

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The Problem With Mold

One problem that often occurs after a flood is the development of mold. Mold growths, or colonies, can start to grow on a damp surface within 24 to 48 hours. Molds digest organic material, eventually destroying the material they grow on. In addition to the damage molds can cause in your home they can also cause mild to severe health problems.

If your home has water damage due to flooding, sewage backup, plumbing or roof leaks, damp basements, overflows from sinks or bathtubs, or high humidity, mold and mildew will develop within 24-48 hours of water exposure. Even worse, it will continue to grow until steps are taken to eliminate the source of moisture and effectively deal with the mold problem. Mold on Walls

Additional information about mold and clean up can be found at:

 

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Protecting Your Home From Back Flow

The sewage/septic system is designed to remove sewage from a house. If flood water enters the system, the sewage can backup and enter your home. To help prevent this, install a backflow valve in the sewer line. The backflow valve is opened by the flow of sewage exiting your home but closes when the flow reverses preventing sewage from backing up into your home. Keep these points in mind when considering installing a backflow valve:Photo of Backflow Valve System

  • For your own safety, changes to the plumbing in your house must be done by a licensed plumber or contractor, who will ensure that the work is done correctly and according to all applicable codes.
  • Some valves incorporate the advantages of both flap and gate valves into a single design. Your plumber or contractor can advise you on the advantages and disadvantages of the various types of backflow valves.
  • Valves should be installed on all pipes that leave the house or that are connected to equipment that is below the potential flood level. Such valves may be needed on washing machine drain lines, laundry sinks, fuel oil lines, rain downspouts, and sump pumps, as well as sewer/septic connections.
  • If you have a sump pump, it may be connected to underground drain lines, which may be difficult to seal off.


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More Information:

Information complied from:
FloodSafe, a Publication of FEMA and WMD Emergency Management Division

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