October 30th, 2026
Low water pressure cannot be ignored, as it can impact fixtures, equipment, and upper floors. What if the water supply cannot provide the pressure your building requires? Water booster pumps can increase and maintain pressure if the supply falls short. But how do you select a pump that meets the building’s requirements?
Stay with us while we share the considerations for choosing a water booster pump.
There are several potential reasons why pressure may be too low. Pressure can drop because fixtures are used at the same time, piping is undersized, elevation changes occur, fittings reduce flow, or demand changes pressure. In other words, the pressure may be normal at the main but too low on the upper floors. The higher the water has to go, the more pressure is needed.
First, determine where and when the low pressure is happening. A water booster pump can increase the pressure, but it should be carefully sized for the application. Not just an enlarged pump for a larger building.
A booster pump may be needed if the water supply pressure falls short of what the building requires.
Booster pumps are frequently used in multi-story residential buildings, commercial buildings, hotels, institutions, industrial and manufacturing facilities, large plumbing systems, buildings with changing water demand, and where upper floor pressure is inadequate.
So, instead of asking, “Do I need more pressure? “ask “What pressure and flow does the building need?”
This distinction matters because oversized pumps create excessive pressure, while undersized pumps may not provide enough.
Let’s begin with what the building actually needs: pressure and flow.
The pump must provide enough pressure to overcome system losses plus static pressure (elevation). A proper water booster pump calculation should include:
For example, the booster pump for a small commercial building will be very different from one for a multi-story apartment building.
A qualified water pump supplier can help determine the required duty point and what equipment can handle the application.
Water demand varies throughout the day in most buildings. At 7 am, multiple fixtures may be in use. At other times, demand may be light.
A standard booster pump may not be enough for a building with varying demand. Variable speed drives let the pump adjust speed to flow demand, rather than running at a single speed.
By adjusting the speed, the discharge pressure can be maintained. Variable speed drives can be a good option for buildings with changing water demand.
This indicates that the pressure needed to supply fixtures on upper floors is too low. As water is pumped higher, the pressure must increase to overcome static pressure.
In simple terms, water must be “pumped up” to reach higher floors. The pump must provide sufficient pressure at the highest fixtures. The pump is sized based on the highest point of pressure loss.
Keep in mind that not only the building height is a factor, but also friction loss through the piping and fittings, and the pressure required at the fixtures or equipment.
Horsepower and pipe size will not automatically select a suitable booster pump.
It depends on the application. The required pressure and flow will determine if a single pump or multiple pumps will be needed.
Multiple pumps can be used in larger buildings, but they add complexity.
The pumps should be selected to suit the building, not the other way around. Larger buildings may need multiple pumps to supply water demand. Some applications can be served by a single pump. Consider the building’s needs to determine the most suitable configuration.
First, we will need to know the application. That means knowing the water pressure at the main, what pressure is needed at the discharge point, the building height, pipe size, fittings, flow demand, and the number of fixtures. There are other considerations as well.
Peak flow demand and average demand will affect pump selection. So will the electrical service and space available for the booster pump
Horsepower and pipe size aren’t the only factors when choosing a booster pump for commercial, industrial, or building applications. Pennsylvania water booster pump suppliers can help you choose the right booster pump for your application.
Pump and control suppliers can help ensure the equipment is matched for the application.
Callaghan Pump carries water booster pumps suitable for commercial, industrial, and building applications. Our expert staff can help you select the right booster pump configuration for your application.
If you are considering a water booster pump and need help with the selection process, contact us to discuss your requirements. Get in touch.
john@callaghanpump.com,
eileen@callaghanpump.com,
dan@callaghanpump.com,
sales@callaghanpump.com,
service@callaghanpump.com
