If you are replacing your old, worn out roof covering with new asphalt shingles, make sure they have a Class 4 rating under Underwriters Laboratories' (UL) 2218 standard. A Class 4 rating tells you a sample of the product did not crack when hit twice in the same area by a two-inch steel ball.
Check Drain Plug: Install a floating floor drain plug at the current drain location. If the floor drain pipe backs up, the float will rise and plug the drain.
Install a Sewer Backflow Valve: If flood waters enter the sewer system, sewage can back up and enter your home. To prevent this, have a qualified, licensed plumber install an interior or exterior backflow valve. Check with your building department for permit requirements.
If you are retrofitting a backflow value, check with your building department for permit requirements. Be sure to talk to a professional home builder, architect, contractor or building supply retailer for other backflow mitigation tips.