Monday, March 14, 2011

Preparing your home for floods

If your home is in a location where seasonal flooding may occur, you need to know how to prepare your home to resist or survive flooding. Flooding can occur in a number of ways.

Sub-surface water leaks

These occur when groundwater levels rise enough to enter the house through cracks or openings in foundations, basement slabs, or sumps and foundation drainage systems. University of Minnesota Extension housing technology educator Richard Stone said, "You can prepare for this degree of basement flooding by raising the furnace, water heater, appliances, and storage items an adequate distance above the floor using waterproof blocking."

Spring run-off and minor surface flooding

"During spring run-off or surface water flooding events, the amount of water in foundation drainage systems increases the demand on the sump pump system," Stone said. He advises the following:

Check the ejection pipe, sump, and sump pump to be sure that they are functioning properly.

If prolonged flooding or a power outage is possible, consider keeping a spare sump pump and a gas powered electric generator available. Store generator fuel safely and operate the generator in a safe location where exhaust fumes cannot enter the home.

Sewer backups

These can occur even if the blockage or flooding is some distance from your home.

To protect your home, consider having a valve or one-way check valve installed where the sewer main leaves the house. A plumbing professional can help you determine the best method and location. If you do not have a valve installed to block the sewer main, temporary compression plugs can be inserted in floor drains and plumbing drain openings.

"Remember that a sewer system blockage could force water higher up in the home's drainage system than expected," said Stone.

Major Surface Flooding

Streams and rivers overflowing their banks present the greatest threat of structural damage to the home.

According to Stone, if the home is outside areas protected by dikes, and the foundation has been strengthened or braced and sealed sufficiently to withstand the external water pressure, it may be possible to keep the basement dry using gas powered pumps. If the basement has not been reinforced and is incapable of withstanding the force of floodwaters, allowing the basement to fill with water may protect the foundation from structural damage by keeping the pressure similar on both sides of the foundation walls and floor.

If there is still time before the flooding, move stored items, furniture, and appliances to a safe upper level of the home or to a safe location outside the flood zone.

Before the home is flooded, shut off the water, gas, and electricity. After flooding clean-up and repairs, your utility company may require that service be restored only by trained utility representatives.

Barb Liukkonen, a water quality specialist, says to prepare water wells when major surface flooding is likely. To do this:

Make sure your well has a tight fitting waterproof cap. Wrap cap and well casing with durable sheet plastic and duct tape, then sand bag around the well. Ensure that backflow prevention valves are in place. Turn the well-pump electricity off just prior to the flood, and keep it off until flood waters recede. Buy or fill sanitized containers with water. Store them where they won't be flooded, so you have some safe drinking water until your well can be put back in service.

If flood waters inundate your well head, you will need to test the water to make sure it's safe even if you have followed the pre-flood recommendations.

Additional resources

Fact sheets and videos with research-based tips on immediate and long-term flood issues

Flood Information Line: 1-800-232-9077,  

For questions about water, crops, horticulture, and climatology issues

AnswerLine: 1-800-854-1678,  

For questions about cleaning, stains, mildew, and food safety issues

 By - Richard Stone, housing technology educator; and Barb Liukkonen, water quality specialist, University of Minnesota Extension

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