If your home is at risk for serious ground water damage from flood or heavy rains, buy federal flood insurance. Buy a policy limit at least high enough to cover your maximum probable loss. Then reduce that amount by the value of all furnishings, carpet, wall coverings, and so on, below ground if you have no walkout, since those items won't be covered. Be sure to buy coverage well in advance of any potential flood, because the NFIP policy has a 30-day waiting period.

For almost everyone else with any potential risk from rain runoff or seepage, install a sump pump system with a guarantee from a reputable firm with good references. It's far less expensive than you'd guess. And it costs considerably less than uninsured water damage claims. Buy optional sump pump failure Homeowners coverage for the lesser of the maximum probable loss or the maximum coverage available.

Buy at least some sewer backup coverage unless you can prevent a backup with a one-way valve in your sewer pipe, or unless your lowest level is unfinished. Buy enough to cover the maximum probable loss or the maximum available, whichever is less.