"Once the water reaches the level of your floor and goes an inch above, you have significant damage," Reinhold says.
It's important to know the flood level at your home -- an official measure of how high floodwaters could rise where you live. You'll find this information by checking the online flood maps on the Federal Emergency Management Agency, or FEMA, website. Your local building department and your insurance agent will know this, too.
Short of putting your home up on stilts, here are six measures that will offer some protection if flooding occurs.
Be sure to use licensed and insured contractors to make any modifications. Check with your local building department about permit requirements.
Safeguard in-home electrical and climate systems
Raise switches, sockets, circuit breakers and wiring at least a foot above the expected flood level in your area, the IBHS website advises.
Modify your furnace, water heater and any other anchored indoor equipment so that it sits above your property's flood level.
Anchor and raise outdoor equipment
Fuel tanks, air-conditioning units and generators should be anchored and raised above your flood level.
Unanchored fuel tanks can break free, and severed supply lines will contaminate surrounding ground, the IBHS warns.
Jose Mitrani, engineer and professor at the OHL School of Construction at Florida International University in Miami, cautions that electrical power units and generators should never sit on the ground.
"These backup facilities will be inundated (by water) and useless," he warns.
Modify water valves
A flooded sewer system can cause sewage to back up into your home. So that you won't find yourself knee-deep in you-know-what, install an interior or exterior backflow valve, IBHS advises.
The Federal Alliance for Safe Homes, or FLASH, recommends gate valves. They are more complex, and you operate them by hand. But they provide stronger seals than flap or check valves, which open automatically to allow water to flow out and then close when water tries to get in.
Valves should be installed on all pipes entering the house, FLASH advises.
Determine how water flows around your house
Called the grading or slope, the angle of the ground can direct water to or from your house. Obviously, it's best if the home was built so that water drains away from the building.
This is easy enough to determine by watching how water flows or accumulates during an average rainstorm, says FLASH President Leslie Chapman-Henderson.
If your street is prone to standing water even after a fairly ordinary rainstorm, talk to your county planning or environmental services department, advises Chapman-Henderson. "A major part of their job is water flow, and they can make suggestions."
Opt for a major retrofit
If your home floods frequently and moving isn't an option, you may need to take drastic and costly measures.
FLASH's home safety program suggests three options:
- Raise your home on piers or columns so that the lowest floor is above the flood level. If that sounds expensive -- well, it would be. Experts tell FLASH that such an undertaking would cost $20,000 and up, Chapman-Henderson says.
- "Wet-proof" your home by installing foundation vents that would allow water to flow through the building, instead of rising inside and causing more damage. You'd need at least two vents on different walls. A 1,000-square-foot house would require 7 square feet of flood vents, according to FLASH.
- Do some "dry proofing" by applying coatings and other sealing materials to your walls to keep out floods.
Take last-minute measures as waters rise
- Clear gutters, drains and downspouts.
- Move furniture, rugs, electronics and other belongings to upper floors, or at least raise them off a ground floor.
- Shut off electricity at the breaker panel.
- Elevate major appliances onto concrete blocks if they're potentially in harm's way from flooding.