What Is a Water Booster Pump and How Does It Work?

Posted by
John Woodard on October 23, 2023

water booster pump increases water pressure and volume to your faucet or shower head. If you have ever tried to shower under a trickle of water and had to turn in circles just to get wet, then you are well aware of the nuisance of low water pressure. For homes that struggle with simple tasks due to low water pressure, a water booster pump may be the perfect solution. In this article, you can find information about what a booster pump is, how it works, how to size one, and the best booster pumps for your application.

What is a water booster pump?

A booster pump is a device that increases low water pressure and flow. It provides the extra boost needed to bring your water pressure to the desired level. A water booster pump provides pressure to move water from a storage tank or throughout a whole house or commercial facility.

What causes low water pressure?

Low water pressure can be the result of issues inside or outside the home. Five common causes of low water pressure include gravity, distance from the water source, low city water pressure, additional water systems, and plumbing problems.

1. Gravity

Gravity either drives or slows water flow. The higher the elevation of water’s destination, the greater the pressure needed to deliver it. One gallon of water weighs over 8 pounds. If water travels uphill or up several floors, it must fight gravity on its way. Buildings lower than their water source may not experience the same problem. Skyscrapers, apartment buildings, and homes and businesses with multiple stories require a large booster pump to move water up many stories.

2. Distance from the water source

Two factors that affect water pressure are the distance from the water source and the size of the pipes. If your home or business sits at the end of the water supply line, the water flow may be low by the time it reaches you. If your pipes are small, less water will be able to run through your fixtures at one time.

3. Low city water pressure

Your house may be below the water supply line, your plumbing pipes may be clear, and you still have low water pressure. Sometimes low water flow results from low-pressure water from your local water plant.

4. Additional water systems

Additional water treatment systems or other water fixtures to your home bring you fresh water but may decrease your water pressure. Adding a booster pump can restore your water pressure.

5. Plumbing problems

If low water pressure is the result of gravity, transportation, or additional systems, a water pressure booster may fix the issue. Other times, however, plumbing problems may be the cause. Before buying a water pressure booster, check your plumbing. The pipes may be clogged, or the pressure reducing valve may need adjusting.

How does a booster pump work?

Booster pumps use a motor-powered impeller that moves water as it enters through the inlet and exits through the outlet. Booster pumps differ according to how they suck water in and push it out. Some water booster pumps use a spinning propeller, while others use an oscillating diaphragm. Pumps with oscillating diaphragms propel water using two oscillating or rotating plates, one with cups and one with indentations. As the plates roll together, they compress the cups and force the water out. As the plates roll open, more water is sucked in.

What are the components of a booster pump?

Most water booster pump, no matter who the manufacturer contain the same core components:

  • Motor
  • Impellers
  • Inlet and outlet
  • Pressure or flow sensing device

The Davey pump pictured below has a sensing device that helps manage and maintain a level of pressure. 

Davey pumps

Do water booster pumps increase water pressure and flow rate?

A water booster pump increases water pressure, forcing the water to flow at a faster rate through plumbing pipes. However, keep in mind that, as the pressure required to move water increases, the flow rate decreases.

Think about putting your thumb over a garden hose. As you do, water comes out at a higher pressure, but the flow rate is restricted because of your thumb. A booster pump works in the same way. It provides the most water at the greatest flow rate under low pressure. If water moves out of the pump without any kind of restriction, it moves at a greater flow rate. When a pump is installed in a house where the water must travel uphill and around bends in pipes through a kitchen faucet, the flow rate is slower and the pressure from the pump is higher.

Types of booster pumps

There are two main types of booster pumps: single-stage and multi-stage pumps.

Single-stage booster pumps use only a single impeller. As a result, they are only used in locations where less pressure is required. Multi-stage booster pumps, on the other hand, include multiple impellers for high-pressure applications. These pumps can be used to send water through winding pipelines up several stories.

How are booster pumps used?

Booster pumps can be found in both residential and commercial buildings. They increase low water flow in water systems or industrial equipment and transport water from a lake, pond, or storage tank for use in a home or commercial building. A household that doesn't receive enough pressure from the city water supply must use a pump to increase low water pressure. Likewise, a hotel needs a large commercial booster pump to send water all the way to the top story. 

A booster pump is also used to re-pressurize water from a storage tank and send it to a faucet or throughout a home. In a rain harvesting system, for example, water collects in a storage tank. In order to use it to flush toilets or wash laundry, the water must be pumped out of the tank and into the house with a water booster pump.

Learn more: How to conserve rainwater at home with a rainwater harvesting system

Residential booster pumps

A single water booster pump can boost water pressure throughout an entire house. Sometimes, well water users want to increase the flow from a low-recovery well to their home because it does not produce enough water to keep up with household demand. A water pressure booster pulls water from the well storage tank to pressurize the water in the house.

A private well that does not produce enough water to keep up with demand requires a storage tank for the well to fill over time and a home booster pump from the tank to keep up with daily demand.

Learn more: What are the parts of a well water system?

Booster pump with an expansion tank

An expansion or hydropneumatic storage tank can enhance a boosted system. The tank gives water extra room to go when it expands and prevents the booster pump from cycling on and off each time you turn the faucet on. Flow switch actuated pumps may hesitate on start-up. A small expansion tank prevents this hesitation. A larger tank holds a volume of water referred to as drawdown. This amount of water draws out of the tank before the pump turns back on. A larger tank can provide higher drawdown volumes in a private well system to significantly reduce pump cycles.

booster pumps

Do I need a booster pump?

A booster pump is recommended if you have low water pressure not caused by a leak or need to increase water pressure for a certain application.

Questions to ask when shopping for a booster pump:

  1. What is my water flow rate? Calculate how many gallons of water you get per minute, taking all fixtures into consideration. Learn how to calculate flow rate
  2. How much water do I need? Consider how much water your household or business uses. 
  3. Is the water source above or below the pump? Think about whether or not your water must travel uphill or up several stories.
  4. How much pressure do I need? Many people prefer high water pressure when taking a shower, but pressure that's too high can destroy plumbing, fittings, and appliances.  Most homes have a pressure reducing valve where the water line enters the house to maintain the water pressure. Pressure over 60 psi wears the household plumbing system.

    Which booster pump you need depends on how much water you use, the desired pressure, and the location of your water source. If you have a large house, for example, you may need a booster pump capable of supplying pressure to the second or third floor. Applications like reverse osmosis systems with low feed pressure or water with a high TDS (total dissolved solids) require a lot more pressure.

    How to size a booster pump

    To size a booster pump for your specific application, ask these questions:

    • Do you have a two-story, four-bedroom, one-bathroom house?
    • Are you moving water a significant distance?
    • How far away is your water source?

    Pumps with a single impeller are not good at drawing water from a distance. If you want to use water from a pond for irrigation, then you need something with more horsepower to pump the water a long distance. Water weighs eight pounds per gallon. If water must travel up a one-inch pipe that climbs several feet, then the pump must push a significant amount of weight.

    Tips for installing a booster pump

    Where to install a booster pump

    A booster pump is installed right where you need to move water from. For example, in a household with low water pressure, you should install the pump on the main line where water enters the house. Plug in the inlet and return the outlet to the plumbing supply. When installing a booster pump, consider the following:

    • Always have a bypass in case the pump malfunctions. A bypass allows you to isolate the pump if it fails and you need to troubleshoot it. You can bypass the pump and still get water into the house.
    • Test the pump before connecting it to the house. Sometimes, a leak may cause the pump to cycle due to low flow rate. Cycling causes the pump to start and stop in rapid succession. 
    • Water booster pumps are activated by flow rate or by pressure or by both. If you find a leak, then isolate the pump and test it to make sure the pump is not the problem. Once tested, you can find the cause and fix the leak. 

    How to keep your booster pump quiet

    To keep a booster pump quiet, you need to factor in the type of pump used and the materials around where the pump is installed. Think about pump vibration during installation. The way you install a booster pump can enhance the noise it makes if you are not careful. Never install the pump directly to copper lines because the vibration of the pump will transfer to the copper and cause excessive noise. Instead, use a flex connector for the inlet and the outlet to minimize the sound from vibration. 

    Best water booster pumps

    Best booster pump for small homes – Davey BT14-45

    The Davey BT14-45 is ideal for small two-story and long one-story homes. It delivers a nominal flow of 14 GPM and a maximum boost of 60 PSI. This pump features a multistage impeller, stainless steel construction, corrosion-resistant motor, and protection from high temperatures. The Davey BT14-45 operates at around 55 decibels, making it a quiet yet efficient booster pump for your home.

    Best booster pump for large homes - Davey BT30-30

    The Davey BT30-30 is a quiet, efficient pump that has a nominal flow of 30 GPM and a maximum boost of 50 PSI. Its single impeller booster system delivers a compact, quiet solution for low water pressure. This pump features the Torrium 2 Pressure System Controller, a system that adapts to changing conditions and outsmarts every-day problems. The Torrium 2 controller also reduces installation and maintenance issues because of its ability to protect itself when problems arise. The Davey BT30-30 comes with a 3-year warranty, making this pump a safe and effective option for your home.

    Best booster pump for irrigation – Grundfos Scala2 3-45-1

    The Grundfos Scala2 3-45-1 is a 115-volt booster pump that is ideal for irrigation, water supply, and domestic applications. It operates at an extremely quiet 47 decibels, about the noise level of a light rainfall. This pump comes with a built-in screen and intelligent pump control that ensure water pressure is ideal for every situation. When no water is available to run through the pump, the pump shuts itself off to protect from overheating and motor damage. The Grundfos Scala2 3-45-1 is an excellent economical choice for your home irrigation system.

    Best technological booster pump – Grundfos Scala1 3-45-1

    The Grundfos Scala1 3-45-1 is a fully integrated, self-priming pump designed for domestic and small commercial applications. It comes with built-in Bluetooth connection that allows you to monitor and customize your pump on the Grundfos GO app. This pump is good for both indoor and outdoor applications and runs at a noise level of about 55 decibels. With its user-friendly design and intuitive app control, the Grundfos Scala1 3-45-1 is excellent for your home.


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