How to Install a Water Pressure Booster Pump
Updated March 2, 2026
Increase low water pressure throughout your house with a booster pump on the main supply line -- sizing, placement, and electrical connection.
Overview
If your house water pressure is consistently below 40 PSI and the water utility confirms adequate street pressure, the problem is between the meter and the house -- a long service line, undersized pipe, or elevation change. A booster pump on the main supply line increases pressure to a target of 50-60 PSI throughout the house. It is an inline pump with a pressure switch and a small expansion tank. Water enters at low pressure, the pump boosts it, and the pressure switch maintains the target. Installation requires cutting into the main line, mounting the pump, and connecting to a dedicated electrical circuit.
What You'll Need
Safety First
- A booster pump without a pressure relief valve can over-pressurize the system. Install a pressure relief valve or use a pump with a built-in pressure switch that shuts off at the target pressure.
- Booster pumps need a dedicated 120V or 240V circuit depending on the model. An electrician should install the circuit if one does not exist.
- Do not boost pressure above 80 PSI. Excessive pressure damages fixtures, appliances, and pipe joints. Install a pressure gauge downstream of the pump to monitor output.
Step-by-Step Instructions
- Verify the Problem Is Low Supply Pressure
Attach a pressure gauge ($10-$15) to an outdoor hose bib near where the main enters the house. Read the pressure with no fixtures running. Below 40 PSI confirms low pressure. Also check: is the main shut-off valve fully open? Is there a pressure reducing valve (PRV) that is set too low or has failed? A stuck PRV restricts pressure and is a cheaper fix ($50-$150) than installing a booster pump. Rule out valve issues before buying a pump.
Tip: If pressure is fine at the hose bib near the main but low at distant fixtures, the problem is pipe sizing or internal restrictions -- not supply pressure. A booster pump will not fix undersized pipes or clogged galvanized lines. - Size the Pump
Booster pumps are rated by flow rate (GPM) and pressure boost (PSI). Calculate your peak demand: 2-3 fixtures running simultaneously = 5-8 GPM typical. Calculate the pressure boost needed: if incoming pressure is 25 PSI and you want 55 PSI, you need a 30 PSI boost. A pump rated for 10 GPM at 30 PSI boost covers most residential needs. Top residential brands: Davey BT20-30 ($300-$500), Grundfos MQ3-45 ($350-$500), Amtrol RP-15HP ($250-$400). All include a built-in pressure switch and check valve.
Tip: The Grundfos MQ3-45 is the most popular residential booster pump. It includes the pump, motor, pressure switch, check valve, and flow sensor in one compact unit. No external pressure tank needed (it has a small internal one). Plug-and-play for most installations. - Install the Pump on the Main Line
Turn off water at the meter. Cut into the main supply line after the main shut-off valve and before the first branch. Install the pump inline with flow direction matching the arrow on the pump housing. Use union fittings on both sides of the pump for easy future removal and service. Install a pressure gauge on the outlet side to monitor output. Install a small expansion tank ($40-$80) on the outlet side to absorb pressure spikes when the pump cycles. Connect electrically to a dedicated circuit.
Tip: Union fittings on both sides of the pump are essential. Without them, removing the pump for service means cutting the pipe. Union fittings let you disconnect the pump in 2 minutes with a wrench. - Set the Pressure and Test
Turn on the water at the meter. The pump should activate and pressurize the system. Adjust the pressure switch to your target -- 50-60 PSI is ideal for most homes. Open faucets throughout the house and check pressure: every fixture should have noticeably improved flow. Listen to the pump -- it should run when water is flowing and stop within seconds of closing all faucets. Check the pressure gauge: should hold steady at the set point. Check all new connections for leaks under full pressure.
Tip: If the pump cycles on and off rapidly (short-cycling), the expansion tank is not sized correctly or is waterlogged. The tank absorbs small pressure drops from thermal expansion and minor water use so the pump does not start for every trickle.
Pro Tips
- A booster pump is the solution for homes at the end of a long municipal supply line, homes on a hill above the street level, or homes with a well system that has lost pressure capacity.
- The pump runs only when water is flowing (demand-activated). When no faucets are open, the pump is off and uses no electricity. Average annual electricity cost: $50-$100.
- Install a sediment pre-filter before the booster pump. Sediment damages the pump impeller and check valve over time. A $5-$15 inline filter protects a $300-$500 pump.
- Well water systems with low pressure may need a larger pressure tank ($200-$400) rather than a booster pump. The pressure tank stores pressurized water and the well pump fills it. A larger tank reduces pump cycling and maintains more consistent pressure.
- A booster pump does not increase the volume of water available -- it increases the pressure. If the main supply line delivers only 5 GPM, the pump cannot boost that to 10 GPM. It can deliver those 5 GPM at 55 PSI instead of 25 PSI.
When to Call a Pro
Call a plumber if you are not comfortable cutting into the main supply line and working with electrical connections, if the low pressure is caused by a corroded galvanized service line from the street (needs replacement, not boosting), if you need a well pump pressure switch adjusted or replaced, or if the booster pump needs a 240V circuit that does not exist.
Frequently Asked Questions
When should I call a plumber to install a water pressure booster pump?
Call a plumber if you are not comfortable cutting into the main supply line and working with electrical connections, if the low pressure is caused by a corroded galvanized service line from the street (needs replacement, not boosting), if you need a well pump pressure switch adjusted or replaced, or if the booster pump needs a 240V circuit that does not exist.
What are some expert tips to install a water pressure booster pump?
A booster pump is the solution for homes at the end of a long municipal supply line, homes on a hill above the street level, or homes with a well system that has lost pressure capacity. The pump runs only when water is flowing (demand-activated). When no faucets are open, the pump is off and uses no electricity. Average annual electricity cost: $50-$100. Install a sediment pre-filter before the booster pump. Sediment damages the pump impeller and check valve over time. A $5-$15 inline filter protects a $300-$500 pump. Well water systems with low pressure may need a larger pressure tank ($200-$400) rather than a booster pump. The pressure tank stores pressurized water and the well pump fills it. A larger tank reduces pump cycling and maintains more consistent pressure. A booster pump does not increase the volume of water available -- it increases the pressure. If the main supply line delivers only 5 GPM, the pump cannot boost that to 10 GPM. It can deliver those 5 GPM at 55 PSI instead of 25 PSI.
What tools do I need to install a water pressure booster pump?
You will need: Booster pump with pressure switch ($200-$600), Pressure gauge ($10-$15, for monitoring output pressure), Expansion tank ($40-$80, to absorb pressure spikes), Tube cutter or PEX cutter (for main line connection), Union fittings (for easy pump removal during service), SharkBite or solder supplies (for pipe connections), Dedicated electrical circuit (120V or 240V depending on pump model).
When should I call a professional instead of doing this myself?
Call a plumber if you are not comfortable cutting into the main supply line and working with electrical connections, if the low pressure is caused by a corroded galvanized service line from the street (needs replacement, not boosting), if you need a well pump pressure switch adjusted or replaced, or if the booster pump needs a 240V circuit that does not exist.
How difficult is this project?
This project is rated advanced. This requires significant plumbing experience. Consider hiring a pro.
How long does this take?
Plan for approximately 2 - 4 hours. First-timers may need extra time.
How much will this cost?
The estimated cost is $200 - $600 for the pump; $100 - $300 for fittings and electrical. Costs vary by location and materials chosen.