Storms during the Spring knock out electrical power and we are quickly faced with the possibility of overflowing sump pits in basements and crawlspaces. I have seen it hundreds of times and most recently in Frankfort and Orland Park. It's amazing how many home owners have not installed a backup system given the risk of damage to any home system, component and personal property. Generators are the best but few home owners can afford them. Next, is the water pressure backup system. It's more expensive than battery systems but there is no electricity involved. You never have to worry about a battery draining to the point where it becomes useless. Domestic water is used to drain the pit and the principle is based on the Venturi effect. The diagram below (provided by Gardian) illustrates how it works.
Finally, is the battery backup. It's not might as reliable as a generator or the water pressure backup but it is better than no backup at all. I have linked an old article and diagram about a simple battery installation from The Family Handyman (June 2003 p.14)...
Battery Backup for Sump Pump
