Advice on Storm-Related Flooding

By Denise DiFulco
Special to The Washington Post
Thursday, June 11, 2009

Never mind the heavy rainstorms of the past week: Hurricane season began June 1, and the National Oceanic and Atmospheric Administration is predicting a near-average year. That means a 70 percent chance of having nine to 14 named storms, four to seven of which could become hurricanes, including up to three rating a Category 3, 4 or 5, the most severe classification.

The Washington area is always a potential target for these tropical tempests, along with the flooding and power outages that result from high winds and heavy rain. Preparedness can go a long way toward keeping your home dry. Below are answers to frequently asked questions about flood risks, along with advice on what you can do to protect your home.

How do hurricanes cause floods in the home?

The ways in which water can enter your home during and after a hurricane are too numerous to list. If you live in a flood plain, chances are there's a body of water nearby that can overflow directly onto your property. There's only so much you can do in that situation.

Rain that falls heavily for a long period can force water into normally dry basements. That's because when the ground becomes saturated, hydrostatic pressure on foundation walls increases. "The water has to go somewhere," says Glen Izett, a manager for Phoenix Home Services in Burke. "It's going to take the path of least resistance." That path is frequently the joint between foundation walls and basement floors, Izett says. Any cracks in the foundation also can provide an entry point.

Can a sump pump prevent that from happening?

A sump pump is generally installed in the lowest part of a basement or crawl space in a pit dug into the ground. As water accumulates underground and hydrostatic pressure increases, water is forced into the pit. Once it reaches a certain level, the pump turns on and moves the water through a pipe away from the home. "Installed correctly, it relieves the pressure around the house," Izett says.

What about French drains? Do they provide more protection?

A French drain is a gravel-filled trench dug along the perimeter of a basement that redirects groundwater away from the home's foundation. Although a French drain can relieve hydrostatic pressure, installing one is an expensive and messy job that isn't right for all homeowners, Izett says. That's because the buildup of groundwater caused by rainfall isn't necessarily the only cause of the problem. Incorrect grading around a house, for instance, will cause water to accumulate and sit along foundation walls. There might also be cracks or other structural flaws in the foundation.

"When you get into more-complicated problems, it's better for the homeowner to hire a structural engineer," he advises. "A drainage contractor doesn't have the education that a structural engineer has."

What steps can homeowners take to prevent water buildup near the home?

There are plenty of common-sense things you can do. For instance, you should keep your gutters and downspouts clean and clear of debris. The water that overflows from gutters doesn't just saturate the area around your home; it also can get under the roof and damage drywall, Izett says. Catch basins and drains outside, especially those adjacent to walk-in basements, should be cleared of sediment and leaves, and any window wells along the base of the home need to be covered to direct water away from the foundation.

Take a walk around your home to see whether the ground and pavement slope away from the foundation walls. Indoors, inspect the foundation (where visible) for cracks where water could seep in. Also, consider painting foundation walls with a concrete sealer, which can prevent moisture under hydrostatic pressure from seeping through.

One thing that homeowners don't always consider is that rain isn't the only problem during a hurricane or tropical storm. Power outages can cause sump pumps to fail, so it's a good idea to install a battery backup, especially if your basement is prone to flooding.

What tools should homeowners have in the event of storm-related flooding?

Oscar Fletcher, operations manager for Capital City Restorations in Rockville, says the first 24 hours after a flood are critical. "That's when mold starts to smell and grow," he says. Mold can cause costlier damage than flooding, so it's critical to remove the water as soon as possible.

You might be able to keep up with water entering your home using a wet-dry vacuum or a water pump from the hardware store. But when you're looking at 40 gallons or more on the basement floor, "that's when you need to take out molding and drywall," Fletcher says. Many homeowners, especially those with high deductibles on their insurance policies, make the mistake of not tearing out damaged construction materials immediately and instead pick up a dehumidifier and a fan to air out the space.

"A lot of people try to take care of it on their own, but some people aren't really good at it," Fletcher says. "They'll open all the windows on a humid day when it's still raining. That's not going to help." If your insurance company hasn't recommended a restoration contractor, you can find one through the Institute of Inspection, Cleaning and Restoration (

What other preparations can homeowners make?

It never can hurt to call your insurance company and double-check what is and isn't covered by your homeowners insurance, Fletcher says. "You should know if you have a backup-of-sewer-or-drain endorsement or a mold endorsement," he says, referring to an industry term for amendments that specify coverage not included in the basic policy.

Your insurer also can give you a quote for flood insurance, if it's not already required by law in your area. Flood insurance policies take 30 days to go into effect, so if you think you might need the protection, you should act before the threat of a storm. You can find additional information about hurricane-related flooding, flood insurance and storm preparation through the National Flood Insurance Program (, as well as the Federal Alliance for Safe Homes (

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