By Glenda Taylor and Bob Beacham | Updated Jul 26, 2022 3:06 PM

BobVila.com and its partners may earn a commission if you purchase a product through one of our links.

Basements are subject to flooding because they’re below grade. If water trickles in, it has no place to go. Many basements have a sump pump installed in a pit in the basement floor to help in these situations. Unfortunately, storms that bring torrential rains and flash flooding also sometimes bring high winds and lightning that can down a power line or knock out a transformer, leaving your home without electricity for hours or even days.

For those times when the power is out, it’s a good idea to have a backup plan for removing water from the basement. The best battery backup for existing sump pumps cycles to remove water and how long a power outage typically lasts in your area. The following sump pump models will step up when the power goes out.

Dependability and durability are among the top considerations when choosing the best sump pump battery backup. When shopping for a backup sump pump, how quickly it can remove water and how long it can run before the battery runs down also are important features.

Battery backup sump pump systems often feature housings made from heavy-duty thermoplastic, stainless steel, or other waterproof materials designed to resist corrosion. The housing also should be sealed to prevent moisture from getting inside the pump’s components.

Like primary sump pumps, the battery back up for a sump pump can be one of two types:

The best sump pump battery backup runs on 12-volt, acid-free batteries. Some manufacturers recommend a battery that’s marine rated, which means it will withstand moisture better than a standard 12-volt battery. A 12-volt battery’s power can range from 40 to 80 amp hours or more, with 75 amp hours being the most common.

The higher the amperage, the more powerful the battery and the longer the backup pump will run. How quickly a battery runs down depends on how much water is entering the sump pit and how often the pump must cycle to pump it out.

For example, if a backup sump pump cycles once every 4 minutes and pumps out 1.5 gallons with each cycle, a 40 amp hour battery might last 32 hours, while a 120 amp hour battery might last closer to 96 hours. However, if the pump cycles every minute, the 40 amp hour battery’s runtime will fall to around 8 hours, and the 120 amp hour battery would last closer to 24 hours.

Another factor comes into play: After four or five years, a 12-volt battery will start to lose some of its ability to hold a charge. This means that an older battery will have less runtime. Choosing a powerful battery—and replacing that battery every four or five years—is the best bet for keeping water from your basement.

Also known as its capacity, a backup sump pump’s flow rate is measured in gallons per hour (GPH). This value estimates the maximum number of gallons it can pump out in an hour when the battery is fully charged. The GPH or flow rate usually appears on the pump’s label or in its product description, and it’s directly related to the power (measured in horsepower) of the pump.

Most sump pump backup systems will remove an average of 1,800 to 2,000 GPH at a 10-foot lift, which means they can pump that much water to a height of 10 feet, which is the typical height necessary to remove water from below a basement to the ground level.

Installing a battery backup sump pump isn’t a difficult project. It requires basic plumbing techniques, but many communities require a licensed plumber to complete the installation. Check with your local building authority to find out the rules in your community.

The simplest type of sump pump backup system to install is a combination unit, consisting of both a primary pump and a backup pump nested together. Because the two pumps come connected, there’s no need to splice the drainpipe to add a second pump, making the installation process relatively simple.

Battery backup sump pump systems should be durable and powerful enough to protect from basement flooding if the power goes out. The following models are some of the best options for keeping your basement dry in any kind of weather.

Those in the market for a new primary pump in addition to a backup pump may want to look no further than the combination sump pump system, the Wayne Basement Guardian premium protection system.

It features a main sump pump that plugs into a household outlet and comes with a nested, ½-horsepower backup sump pump that accepts a 12-volt battery (sold separately). Both pumps are made from cast iron and aluminum, and the unit is submersible.

The primary pump can pump up to 3,840 GPH of water at a 10-foot lift, and the backup pump can pump up to 2,040 GPH to the same lift. This combo unit connects to home Wi-Fi systems, and it syncs with a smartphone to provide alerts when the power is out and the backup sump pump is active.

Get the WAYNE protection system on Amazon, Ace Hardware, and Northern Tools.

Coming in at second place, the Basement Watchdog Special CONNECT sump pump with battery backup is a combination unit that includes both a primary sump pump and a battery backup pump.

This nested, submersible pump is constructed with cast iron and cast aluminum for durability. It’s designed to run on AC unless the power goes out, and then the battery backup pump kicks in. The pump runs on a 12-volt battery, which is not included.

The primary pump is rated to pump 3,200 GPH at a 10-foot lift, and the backup pump is rated to pump 1,730 GPH of water to that same height. For the longest runtime, choose a battery with 75 amp hours or higher. This unit is not Wi-Fi capable, but in the event of a power loss, it will emit an audible alarm.

Get THE BASEMENT WATCHDOG CITS-50 sump pump at The Home Depot or at Lowe’s.

You can protect your basement from flooding without having to spend a lot of money. The Basement Watchdog battery backup sump pump is rated to pump 1,000 GPH at a 10-foot lift. Since it’s a secondary pump only, a primary pump also must be installed with it in the sump basin.

The submersible pump housing is made from heavy-duty thermoplastic to make it waterproof and corrosion-resistant. This affordable backup pump runs on a 12-volt battery (not included) with a 75 amp hour runtime.

Get THE BASEMENT WATCHDOG BWE sump pump at The Home Depot or at Overstock.

With the Zoeller Aquanot sump pump with battery backup, the backup pump doesn’t have to connect to the primary pump because it’s a combination unit. It comes fully assembled, ready for a plumber to install in a basement sump pit. This submersible unit is made of cast iron and thermoplastic components that resist rust and corrosion.

The primary pump is rated at 2,040 GPH with a 10-foot lift, and the ⅓-horsepower backup pump is rated for 1,800 GPH of water with the same lift. This battery backup system also comes with a lockable battery box, which requires a 12-volt battery that’s not included. When the power goes out, it lets you know with a light indicator and an audible warning.

Get the Zoeller sump pump system at Lowe’s.

Made from corrosion-resistant, thermoplastic construction, the Superior Pump battery backup sump pump should provide years of reliable protection from flooding when the power goes out. It comes with an easy-to-remove and clean intake screen filter that keeps debris from entering the pump’s motor. It also comes with a thermoplastic battery box to protect the 12-volt battery (not included) from moisture and corrosion.

The Superior Pump is a backup-only pump, and it must be installed alongside a primary electric sump pump. This battery backup system is rated to remove up to 1,080 GPH of water to a 10-foot lift; for the best results, use a battery with 75 amp hours or higher.

Get the Superior Pump bacup sump pump at The Home Depot, Lowe’s, and Northern Tool.

For high efficiency and flood protection in a combination unit, look no further than the Zoeller ProPack combination primary and backup sump pump system. This nested unit features a primary pump rated to pump 3,660 GPH of water at a 10-foot lift and a backup pump rated to pump 1,800 GPH to the same lift.

This combination unit features an engineered thermoplastic exterior, and the housing is filled with oil and sealed hermetically to protect the pumps. The battery charger has an LED screen that displays the voltage left in the battery and other essential system information.

When the power goes off, the Zoeller combination pump system emits an audible alert. The unit works on both AC for the primary pump and a 12-volt battery (not included) for the backup pump.

Get the WAYNE battery backup system on Amazon, The Home Depot, and Northern Tool.

Receive notifications when the power goes out with the Basement Watchdog battery backup sump pump with Wi-Fi. This submersible, backup-only pump is designed to sync with your home’s Wi-Fi system and send notifications directly to your smartphone via a downloadable app. You also can monitor the pit’s fluid level and the remaining battery charge from your phone.

This battery backup system is designed for use with an existing primary sump pump, and it runs on a 12-volt battery (not included). When the power goes out, it springs into action, pumping up to 1,730 GPH water to a 10-foot lift. In addition to sending notifications to a smartphone, the backup pump emits an audible alarm when the power goes out or when maintenance is needed.

Get THE BASEMENT WATCHDOG BWSP sump pump at The Home Depot, Lowe’s, and Ace Hardware.

For peace of mind in those homes where the sump pump regularly cycles—even when it’s not storming—consider the Basement Watchdog Big Dog CONNECT battery backup sump pump.

This submersible backup pump is rated to pump 2,250 GPH of water at a 10-foot lift, making it the backup pump with the highest GPH rating on this list. It features sealed thermoplastic housing for long-lasting water protection, and it also comes with Wi-Fi capability, so you can download the app on your smartphone and receive notifications.

This is a backup-only sump pump and should be installed next to a primary sump pump. It runs on a 12-volt battery (not included), and the manufacturer suggests using a marine-rated battery for the best results. Users can connect an additional backup battery for double the runtime.

Get THE BASEMENT WATCHDOG 3500 sump pump at The Home Depot or at Lowe’s.

Selected for its ample gallons moved per minute, submersibility, and Wi-Fi compatibility, the WAYNE Basement Guardian is our first choice for the best battery backup sump pump. Made with a primary and secondary pump, this option is for those in need of a heavy-duty pump that can manage to move 2,040 to 3,840 gallons per hour.

Alternatively, the Basement Watchdog BWE system comes with a smaller price tag and is made to be a backup pump only. If you already own a primary pump, this option is meant to move 16 gallons per minute and can be completely immersed. Plus, it comes with a heavy-duty thermoplastic construction and is waterproof and corrosion resistant.

Preventing your home from flooding can save you money and headaches in the long run. The best battery backup sump pumps available can provide peace of mind in case of a flood, storm, or broken water pipe. The above selection of backup sump pumps was selected for their durability, ease of use, connectivity, and lift.

The featured pumps are made with cast aluminum, cast iron, or thermoplastic components to ensure long-lasting durability. Some are sealed hermetically to protect the internal components and battery. Many of the above picks are also made to be submersible and with 10-foot lift to remove water quickly and from the source.

Each unit on the list has the ability to move over 18 gallons of water per minute to ensure sufficient pumping capabilities. In the case of a power outage, many of these picks can also send notifications via smartphone app or through an emitted alarm.

Peace of mind is the most significant advantage of owning a battery backup sump pump. Without a backup pump to remove the water that drains into the sump pump basin, flooding can follow a power outage.

If this is the first time you’ve shopped for a backup sump pump, you probably have some questions. Keep reading to find the answers to some of the most popular questions about backup sump pumps.

Yes, the backup pump is installed in the same sump basin, and when the power goes out, the backup pump begins to pump out water.

Battery backups last until the battery runs down, which can be anywhere from an estimated six hours to 90 hours or longer. The amount of time depends on the battery’s size and how quickly water is flowing into the sump pit.

You probably need a plumber for installation. Similar to installing a primary sump pump, setting up a battery backup sump pump requires connecting a new pipe to the existing system. The process involves installing a check valve and ensuring the fittings are watertight. In many communities, building codes require a plumber to make those connections.

Most battery backup sump pumps are connected to your home’s power unit. If there is a battery backup installed, there will be a battery indicator light that remains green if your battery still has a strong charge.

The best basement sump pump with battery backups include lead-acid batteries. Ensure that your system has this type of battery (if it does not require a different type) before use.

A battery backup sump pump should be tested the same way you test a regular pump. First, fill the pump with water and watch to see if the pump begins to move water. If it doesn’t, be sure that the unit is plugged in or a replacement may be needed.

Then, with your primary sump pump unplugged, watch the water drain from the basin and ensure there are no leaks in the discharge pipe. To be sure, check outside to make sure the water has drained properly.

Wait until the sump pump has completely turned off. If it doesn’t, the pump may overheat and lose functionality. Then, if the water does not drain, you may require a new battery backup pump.

The battery on a backup sump pump should be changed every 5 years.

When installed professionally, the best basement sump pump with battery backup will cost over $900. But, in some cases it may cost up to $1200 or as low as $600. If you were to install the system yourself, the cost will be between $160 and $600.

An emergency sump pump acts as a sensor between your current sump pump and its electrical supply. The primary sump pump will be plugged into a battery backup controller with the backup sump pump. From there, the battery will be connected to an electrical source.

Disclosure: BobVila.com participates in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for publishers to earn fees by linking to Amazon.com and affiliated sites.

Copyright © 2022 Acton Media Inc. All rights reserved.

Articles may contain affiliate links which enable us to share in the revenue of any purchases made.