This is a close up of a primary sump pump (bottom) with a backup pump mounted above it. If the primary pump fails, the backup will run to prevent flooding. 

The sump pump in your home is something you don’t usually think about until there is a torrential rain–or it doesn’t work. This is human nature, so an advisable thing to do is have a backup sump pump system. This is a second sump pump mounted above your primary pump that kicks in if the first one does not work–due to power outage, mechanical failure, or it just can’t keep up.

Types of Sump Pump Backups–Battery and Water Powered

Battery Powered

The most common type is the battery backup. 

A typical battery used to power a backup sump pump

It runs off of a 12V deep cycle batterySome systems have a battery included and some don’t. If you purchase the manufacturer’s (more expensive) battery the warranty may be lengthened–usually increasing to 3 years. Even if it doesn’t come with a battery it will have a plastic box to hold the battery you purchase (which are usually next to it on the shelf).

A typical battery backup
package, with the
indicator panel to
show the status.

The system comes with an indicator panel to give the status of the system, and it will also sound an alarm if the backup is called upon to run. 

One thing to investigate is if the backup runs only on battery power (12V DC) or if it can run on AC household power also. The reason it’s important is if the primary pump fails for mechanical reasons, the backup can run off the house power indefinitely. If it can only run on the battery, it will stop once it drains the battery. 

The downside of battery backups is that they are only a short-term defense. Once the battery is discharged, they are of no help. If the power is off for longer than your battery life, you will have water in your basement. Which leads us to the other type of backup…

Water Powered

A less well-known type of backup is the water-powered backup. This is a pump that uses the municipal water supply to your home. When the water rises in the sump pit it turns on the house water, which then flows through a pump and is discharged outside of your home. The water running through the pump creates a suction (using the Venturi Principle) that draws the water out of your sump pit. Here is a video on how it works.

The advantage of this type of pump is that there is no battery that will run down after a number of hours. The municipal water supply is typically not affected by power outages, and so this backup can run indefinitely with a long-term power outage. 

I know of a home that was for sale and unoccupied. The owner received his water bill and couldn’t figure out why it was so high. He discovered that his primary sump pump had failed and his water powered backup had been pumping the pit for the last month. The water bill was a lot cheaper than a cleanup and remodel in the house he was trying to sell!

The downside of this type of backup is it does not have the pumping capacity of a battery backup. Also, it is not compatible with homes that have well water, because the well pump will not run in a power outage. 

When buying any backup pump and looking at how much water it can pump in Gallons Per Hour (GPH), be sure to check what “head” it is pumping at. The “head” means how high up the pump has to push the water. Normally the sump pit is in the basement, so the water has to go up 10 feet to be discharged. So make sure you are not comparing GPH for one pump at 0 head and another at 10′ head. Zero head is really a marketing trick to inflate the pump’s GPH. Here is a typical chart showing the pumping capacity for a battery backup:

        GPH @ 0 feet:   1380 GPH         
        GPH @ 5 feet:   1380 GPH
        GPH @ 10 feet:   900 GPH     (Notice the drop to 900 GPH, 480 less than 0 head)
        GPH @ 15 feet:   300 GPH

If you are looking for a battery backup system, I would check out
It has ratings, recommendations, reviews, and staff to answer questions.

If you want us to handle finding the right backup system for your home and having a professional plumber install it, please call me at (262) 245-8828.

-John Rees
Property Services Manager