Take a few minutes to look at water powered backup sump pumps too. www.basepump.com
carries the very best in both water- and battery- powered backup sump pumps as well as alarms, leak detection equipment, etc. Basepump is one of the best water powered units on the market and rivals any battery powered system, including their own Hydropump. The key is that there is no battery to maintain or replace and no charger to monitor. The pumping rates are very good, too. Check out the customer reviews you can find online. This is a permanent installation that requires no maintenance.