A flooded basement or crawl space because of a power failure is something homeowners dread, but an ounce of prevention like a backup sump pump is the solution. The pump operates on batteries and does not rely on the local electric utility company for power like a pedestal or submersible pump. A backup pump uses a 12-volt battery kept at full capacity by a charger that’s plugged into a wall outlet, and it alerts you when and if your primary pump stops working. A plumber will charge $648, which includes labor and material, to install a backup battery-operated sump pump. A handy homeowner with experience doing plumbing and electrical projects can buy the pump and plumbing supplies for $400, install it and pocket a 38% saving. This is not an easy-does-it job because it involves several steps; if there’s any doubt about your skills, hire a pro for the project. …