How to Decide Between a Water-Powered Backup Sump Pump vs Battery-Powered
If you are a homeowner wanting to buy a backup sump pump to add to your main electric pump, there are two options available — water powered backup sump pump vs battery powered.
Both of these types of backup sump pumps have their own advantages and disadvantages. The decision over which one would be best for your home will be determined by your water volume needs, your specific plumbing system configuration, and other preferences.
To help you decide which pump type is the right choice for your home, we will discuss the specific attributes of each pump in this article.
The Key Differences Between A Water Powered Backup Sump Pump Vs Battery Backups
The most common sump pump backups use batteries, which means you need to buy the pump itself and then also a battery.
Water-powered backup sump pumps have however been growing in popularity steadily as homeowners start discovering their advantages.
A water-powered backup sump pump runs using the municipal water pressure in the home and you don’t need electricity or batteries at all.
Both of these types of backup sump pumps have been designed to prevent basement flooding if your primary sump pump does not operate. Whether it be due to mechanical failure or a power failure.
The question is, which does a better job and why?
Let’s look at four main criteria to use when comparing a water powered backup sump pump vs battery powered pumps:
- Life Span: What is the lifetime of the pump before it must be replaced?
- Run Time: How long can the pump run continuously or intermittently?
- Cost: What is the upfront and lifetime cost of the pump?
- Pumping Rates: How fast does the pump remove water?
Battery Backup Sump Pumps
Battery backup sump pumps have been used by homeowners much longer than the newer water powered backup pumps.
Their operation is also very easy to understand: a battery runs the pump –straightforward indeed!
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Battery backup pumps normally use marine deep-cycle, AGM, or a similar type of battery. Some are very easy to install yourself.
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Related article: How to Choose the Best Battery for Backup Sump Pump System.
Batteries that are used to operate a backup sump pump will last for a limited amount of time just as any other battery does. A popular manufacturer of battery backups for sump pumps says to replace batteries every three years.
Apart from regular battery replacement, battery backup sump pumps tend to fail mechanically after prolonged use.
If you want to have a backup system that is reliable:
- You’ll have to monitor the battery health.
- Run tests periodically to ensure the pump is operating properly.
- Replace the battery when required. Typically, every 3 to 5 years.
Most battery backup sump pump systems will self-test, monitor, and warn when the battery needs replacement.
Pump Run Time
A study by North Dakota State University found the batteries that are used to run backup pumps can last anything between 4 and 11 hours of continuous running. This time willdepend on the battery capacity, which varied between 40 and 120AH (Amp Hours)
The charge capacity of any battery reduces as it ages. Although a new battery may provide 8 hours of run time, a battery that’s three years old may have a run time of as little as 2 or 3 hours. That’s a crucial difference and you’ll see even less run time after 5 years.
Quite often homeowners experience their basement flooding due to an older battery because they think they are protected by the battery backup. If the power outage lasts longer than the battery charge, your basement can quickly flood as you’ll effectively have no pump at all.
There is a definite limit to how long the pump will keep on running during a power outage, as a battery that cannot recharge will eventually die. You could however mitigate this risk by for example using an additional battery.
Water-powered pumps have a huge advantage because they will run for an unlimited time. This is the best reason to buy one of these types of pumps. There is no need to worry about replacing the battery as they don’t use a battery.
Total Cost of a Battery-Operated Backup Sump Pump
A battery backup sump pump kit typically costs between $200 and $900 depending on the pumping power. You will however also have to buy the battery separately.
Battery-operated backup sump pumps typically use one 12V 100AH deep cycle Absorbent Glass Mat (AGM) type battery.
Depending on the quality of the battery, a typical battery costs between $150 and $250.
Apart from these upfront costs, remember that you’ll have to replace the battery about every 3 years. This increases the total cost over its lifespan significantly.
Pump Rate of an Electric Backup Sump Pump
- Pumps provided with emergency battery backups are typically either 1/3 HP or 1/4 HP. Most backup pumps are rated to pump 800 to 2,000 GPH, depending on how powerful the pump is. That is however only true if the battery is new and fully charged.
- Battery powered backup pumps suffer from greatly reduced pumping rates as they get older.
The pump’s ability to pump at full power reduces over time, the same as the battery’s capacity to hold a charge does. You may notice that your battery backup starts pumping at an ever-slowing rate after only a year or two as the battery gets weaker.
The same happens to a flashlight – the light is bright when the battery is new, but the light gets dimmer over time when you turn it on. It will eventually get to the stage where it doesn’t work at all.
- If you lose power and the backup pump starts running, you will also see the pumping rate will decrease continually the longer the pump operates.
Water Powered Backup Sump Pumps
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Advantages of Water Powered Backup Sump Pumps
No battery maintenance
Homeowners won’t have to check, maintain, or replace a battery or monitor a charger to make sure it’s doing what it’s supposed to with a water powered pump.
A water powered pump protects homeowners while at work or on vacation. Also, owners of vacation properties or rental properties appreciate the protection provided.
Unlimited run time
As your home’s municipal water pressure is used to power a water powered sump pump, they can theoretically run for an indefinite period, providing water is available. This may mean the difference between a dry or flooded basement in multi-day power outages.
Steady flow rate
Unlike battery powered backup sump pumps, water-powered pumps maintain the same pumping rates over time. Since it gets its energy from the municipal water pressure, the pumping capacity will stay consistent irrespective of how long ago it was bought.
Lower Yearly Maintenance
Water-powered pumps last longer than electrical pumps since they have fewer operating parts. They also don’t require as much maintenance, providing they are correctly installed in the sump pit
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Disadvantages of Water Powered Backup Sump Pumps
Although it may seem that water-powered pumps are the perfect choice for any home, they have several disadvantages.
There are some criteria that a home’s plumbing system must meet to use a water powered pump. These include having adequate water flow rate, water pressure, the types of pipes, and any restrictions in the piping.
Typically, a ¾ inch water supply line is required with a flow rate of 20 to 90 gallons per minute. The higher the water pressure, the more water the pump can remove per minute.
If your home has a water well, it must be on a separate power supply from the household’s power supply. Otherwise, the water well will not be able to operate the water powered sump pump.
Water Powered Sump Pumps Pumping Rate
A water powered sump pump typically don’t have the pumping rate that a battery backup pump with the highest volume has. Many pumps have a maximum pump rate of 750-1200 GPH.
The Basepump CB1500 does however delivers quite a bit of pumping power. It will pump 2,000 GPH at 10 feet of lift for a house that has a water pressure of 90 PSI.
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Even the most powerful water-powered pumps do however not compete with an electric sump pump’s pumping volume, such as the Zoeller M53 that pumps 2580 GPH.
Related article: Zoeller M53 Sump Pump Review: 1/3 HP Cast Iron Mighty Mate
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Most water powered systems need at least two gallons of city water for each gallon of water removed.
A backflow prevention device must be installed with a water powered sump pump. This device prevents dirty water from being accidentally sucked into the clean water lines.
A backflow preventer may be part of the water powered sump pump. However, many cities require a more robust backflow preventer. Also, cities may require a professional yearly inspection of the backflow preventer.
A backflow preventer will also reduce the pump’s power by restricting the water flow going to the pump.
Compared to battery powered backup sump pumps, water powered sump pumps are a bit trickier to install. It is crucial that they are installed properly as they connect to the home’s water supply.
It is quick and easy to install an electric pump. On the other hand, a water-powered pump will require plumbing skills and additional parts.
To simplify installation, you may want to consider the Basepump RB750-EZ. This residential water powered sump pump includes an installation kit, which eliminates a lot of effort from the installation process.
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Costs of Water Powered Sump Pumps
Prices for water-powered sump pumps vary widely and are based on several factors. Most pumps cost from $100 to $800 excluding installation. The higher the pump rate, and the more functionality and features, the higher the cost.
We recommend that you spend a little more to get one of the more powerful pumps to prevent yourself from finding a flooded basement!
Water powered backup sump pumps require no electric power or battery to run as they are powered by city water pressure. So, homeowners are trading a lower electric bill for a higher water bill. The scarcity of water and what you are paying for it could add up to a large bill.
The cost of a water-powered backup sump pump varies depending on the quality and style. Although the low-cost models have a shorter life and lower pumping capacities than professional models, they will serve you well enough if there is relatively little water flowing into the sump.
The best water-powered pumps are however still not as expensive as a lower end battery backup sump pump including the battery.
The term ‘backflow’ in the plumbing industry refers to used or dirty water reversing direction and flowing back into a clean water source, such as the municipal water supply.
Water powered backup sump pumps always have discharge pipes filled with dirty sump water.
Since water powered pumps connect to your home’s water supply system, it is critically important that they are installed in a way that prevents the backflow of sump pit water into your town’s clean water source.
To prevent this, plumbing authorities normally specify that homes with water powered sump pumps must install a Reduced Pressure Zone (RPZ) backflow preventer.
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This device does however introduce some complexities and they must normally be reported to the city’s plumbing authority.
They are expensive and cost about $200 to $500. They also require an annual certification by an inspector that costs $40 to $300.
The inspection fee is higher for commercial properties than residential properties. Also, repairs and recertification after repairs will raise the cost. The average inspection fee is about $100.
These Basepump water powered sump pumps come with a built-in “Vacuum Breaker” backflow preventer:
Basepump RB750-AVB Water Powered Backup Sump Pump
Basepump HB1000-AVB High Volume Water Powered Backup Sump Pump with AVB Back-flow Preventer
Basepump CB1500-AVB Commercial Water Powered Backup Sump Pump
Basepump vacuum breakers comply with industry standards (IAPMO Listed, CSA Certified, and ASSE Listed), and most local councils recognize them as an effective way to prevent backflows.
Although the installation of a water-powered sump pump is not quite as easy as a battery-powered pump, it is still possible to do without having to hire an expert plumber.
The first step to take when installing a pump is to read the owner’s manual for exact instructions on how to install and use the pump. As each pump is slightly different, it’s important that you find out what you should be doing.
How To Install A Water Powered Backup Sump Pump
Installing a water powered backup sump pump vs battery powered sump pumps is quite a bit more work and requires additonal parts.
- Some pumps are installed just above the sump pump basin. This is usually accomplished by using clamps to attach to the primary sump pump’s discharge pipe.
One option is to place a piece of wood across the top of the sump basin and attached the water powered pump to the wood with screws.
Pumps are also often installed between the wood floor joists at the basement ceiling.
- Accessing the cold-water line – Cut into the cold water line and run a ¾” diameter pipe into the water powered pump’s inlet. Copper, CPVC, or PEX pipe can be used.
Install a shutoff valve near the water powered sump pump so that the pump can be removed later if required.
Install an RPZ backflow preventer on the city water line between the shutoff valve and the water powered sump pump.
- Installing A Separate Discharge Pipe – Install a PVC discharge pipe from the water powered sump pump to pump the water to the yard outside.
- Testing the Pump – Make sure that the power to the primary electrical sump pump is turned off.Test the water powered sump pump by adding a few gallons of water into your sump basin. The pump should start operating once the water has raised the float.
Summary: Water Powered Backup Sump Pump Vs Battery Backups
When comparing a water powered backup sump pump vs battery backups, it’s very clear that the water-powered option is an ideal backup solution for homeowners who have access to a low-cost municipal water supply.
Otherwise, you must choose a battery backup system.
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