A backup sump pump can spare a lot of damage. Video Backup Sump Pump There are some things to take into account when considering a spare sump pump.
How often does your current sump pump run now? Once or twice an hour or more? Do you store valuables in the basement? Are they on the floor, or on shelves? Is your area prone to power failures?
Adding a 115-volt pump along side your old pump will move more water out of the basement than any of the backup pumps, about 2000 gallons per hour. As a rule, a second pump can be installed next to the old pump and piped into the existing discharge line. This is plan “A” if power failures are rare in your area. You should still store anything of value at least 24 inches off the floor.
Next in water volume is the battery backup pump, it pumps about 720 gallons per hour. The drawback with these units is the maintenance on the battery. The first year or two there should not be a problem. It is the third or fourth year that most of us forget to check the battery. When the battery becomes weak, it may only run an hour or so. Thus not providing much backup protection if it does not last as long as the power failure. Fishermen with a battery powered trolling motors get a bonus here. They can rotate their motor battery with the backup pump battery to insure reliability.
Last but least is the water backup pump. It is a siphon pump powered by household water pressure. It may only pump about 250 gph, however being driven by water it can pump that constantly.
My suggestion when installing a water backup pump is to pipe the discharge line directly out of the house. Let it run out on a splash block or into a gutter so the water discharges at least five-feet from the house.
This will accomplish two things:
1. The siphon pump will move more water if it is in it’s own pipe, not sharing with the electric pump.
2. It will be a visual sign to the homeowner that the electric pump may not be working.
Whatever you do, two pumps are always better than one.