To prepare for a flood, you should:

• Avoid building in a floodplain unless you elevate and reinforce your home.
• Elevate the furnace, water heater, and electric panel if susceptible to flooding.
• Install "check valves" in sewer traps to prevent flood water from backing up into the drains of your home.
• Construct barriers (levees, beams, floodwalls) to stop floodwater from entering the building.
• Seal walls in basements with waterproofing compounds to avoid seepage.

The smartest thing you can do to prepare for floods is purchase flood insurance.