Why Your Well Pump Pressure Drops and How to Raise It

Well pump pressure falls when the pressure tank loses air, when sediment clogs the system, or when the pump itself wears out. The most common fix is adding air back into the pressure tank—a job you can do yourself in about 20 minutes with a bicycle pump or air compressor. If that does not work, the problem is usually a waterlogged tank, a failed check valve, or a pump that needs professional service.

Pressure tanks store compressed air above the water line. When that air cushion shrinks, the pump runs more often and the pressure at your tap drops. You will notice this as weak flow, especially when multiple faucets run at once. The fix depends on what caused the pressure loss, so start by checking the tank itself before calling a technician.

Key Takeaways

  • The pressure tank air charge is the first thing to check—if it has dropped below 2 pounds per square inch (psi) below your pump's cut-in pressure, add air with a bicycle pump or compressor.
  • Drain the tank completely before adding air, because water in the tank prevents the air from doing its job.
  • Your pump's cut-in pressure is printed on the pressure switch; add air to about 2 psi below that number.
  • If pressure stays low after recharging the tank, the problem is likely a waterlogged tank, a failed check valve, or internal pump wear that requires a technician.
  • Sediment in the tank or pipes can block flow and feel like low pressure even when the pump is working correctly.

Check Your Pressure Tank Air Charge First

The pressure tank has two chambers: one holds water, the other holds compressed air. Over time, that air leaks out through the tank's air valve or gets absorbed into the water. When the air charge drops, the tank cannot cushion the pressure swings, and your pump turns on and off more often. You can check the air charge with a tire pressure gauge—the same tool you use for car tires.

Locate the air valve on top of the pressure tank. It looks like a bicycle tire valve. Unscrew the plastic cap and press the gauge onto the valve stem. The reading tells you how much air is in the tank. Compare this to your pump's cut-in pressure, which is printed on the pressure switch (usually a box mounted on or near the tank). If the air pressure is more than 2 psi below the cut-in pressure, the tank needs air.

Do not add air while the tank is full of water. Turn off the pump at the breaker, open a faucet downstairs to drain the tank, and wait until water stops flowing. This usually takes 5 to 10 minutes. Once the tank is empty, you can add air safely.

Add Air to the Pressure Tank

Use a bicycle pump, hand pump, or air compressor to add air to the tank. A bicycle pump works fine for small adjustments; an air compressor is faster if you need to add a lot of air. Attach the pump or compressor hose to the air valve on top of the tank, the same way you would inflate a tire.

Pump air into the tank until the gauge reads about 2 psi below your pump's cut-in pressure. If your pump cuts in at 40 psi (a common setting), aim for 38 psi in the tank. This gives the water room to compress without triggering the pump when ready. Do not overfill—too much air pressure can damage the tank or cause the pump to cycle too often.

Once you have added air, turn the pump back on at the breaker and run a faucet to check the pressure. If the pressure at your tap feels stronger and the pump does not run constantly, the tank air charge was the problem. If pressure is still weak, move on to the next steps.

Drain and Inspect the Tank for Water Damage

A waterlogged tank means water has filled the entire tank, leaving no room for the air cushion. This happens when the rubber bladder inside the tank fails or when the air valve leaks. A waterlogged tank cannot be fixed by adding air—the water will just push the air back out.

To check if the tank is waterlogged, turn off the pump and open a faucet. If water flows for a long time before stopping, the tank still has water in it and is working. If water stops almost when ready, the tank is waterlogged. You can also tap the tank with your knuckles—a healthy tank sounds hollow in the upper half and dull in the lower half. A waterlogged tank sounds dull all the way up.

If the tank is waterlogged, it needs to be replaced. This is a job for a well technician because it involves disconnecting the pump, draining the system, and installing a new tank. Waterlogged tanks cannot be repaired.

Check the Check Valve and Pump Discharge Line

A check valve sits between the pump and the pressure tank. It allows water to flow into the tank but prevents water from flowing back into the pump when the pump shuts off. If the check valve fails, water leaks back down the well, and the pump has to start from scratch each time it turns on. This causes weak pressure and frequent pump cycling.

You cannot repair a failed check valve yourself, but you can tell if it is the problem. Turn off the pump and open a faucet at the lowest point in your house (usually a basement spigot). If water flows out for more than a few seconds, the check valve is leaking. Water should stop almost when ready because the check valve should hold the pressure in the line.

Sediment can also block the check valve or clog the discharge line from the pump to the tank. If you see rust-colored water or particles at your faucets, sediment is in the system. A sediment filter on the pump discharge line can prevent this, but removing existing sediment usually requires flushing the system—another job for a technician.

When to Call a Well Technician

If you have recharged the tank air and pressure is still low, or if the tank is waterlogged, the problem is beyond a straightforward fix. A well technician can test the pump output, replace a failed check valve, install a sediment filter, or replace the pressure tank. They can also diagnose whether the pump itself is wearing out and losing capacity.

Pump wear happens over time as internal seals degrade. A worn pump may still run, but it cannot build pressure the way it did when new. A technician can measure the pump's output and tell you whether it is time to replace it. Replacement is expensive, but a failing pump will eventually stop working entirely, so catching it early prevents an emergency.

Keep records of your pump's age and any service work done. Most well pumps last 15 to 25 years depending on water quality and how often they run. If your pump is in that range and pressure has been dropping gradually, replacement may be more cost-effective than repeated repairs.

Maintain Pressure Tank Air to Prevent Future Problems

Check the tank air charge once a year, ideally in the fall before winter. Cold weather can lower air pressure slightly, and a yearly check catches slow leaks before they become a problem. Keep a tire pressure gauge near the tank so you can check it yourself without calling a technician.

If the air charge drops more than 2 to 3 psi in a year, the air valve is leaking and should be replaced. This is a small, inexpensive part that a technician can swap out in minutes. Catching a leaky valve early prevents the tank from becoming waterlogged.

Avoid letting the tank run completely empty of air. If you notice weak pressure, do not wait—recharge the tank right away. The longer the tank sits without air, the more likely water will fill the space and damage the bladder inside.

Frequently Asked Questions

What is the normal pressure range for a well pump?

Most residential well pumps are set to cut in at 40 psi and cut out at 60 psi, meaning the pump turns on when pressure drops to 40 and shuts off when it reaches 60. Some systems use 30/50 or 50/70 instead. The correct range for your system is printed on the pressure switch. You should maintain tank air pressure about 2 psi below the cut-in pressure.

Can I increase the cut-in pressure to get higher water pressure?

Yes, but only within limits. Raising the cut-in pressure from 40 to 50 psi will increase water pressure at your taps, but it also makes the pump run more often and wear faster. Most technicians do not recommend going above 60 psi cut-in pressure. If you want higher pressure, talk to a technician about whether your pump and tank can handle it safely.

How often should I check the pressure tank air?

Check it once a year, ideally in the fall. If you notice weak water pressure or the pump running constantly, check it when ready. If the air charge drops more than a few psi between checks, the air valve may be leaking and should be inspected by a technician.

What does it mean if the pump runs constantly?

Constant running usually means the tank air charge is too low, the check valve is leaking, or the pump is losing capacity. Start by recharging the tank air. If the pump still runs constantly, the check valve or pump itself needs professional inspection.

Can I use a regular air compressor to add air to the tank?

Yes, a standard air compressor works fine. Just make sure the tank is drained of water first, and do not overfill—stop when you reach about 2 psi below your pump's cut-in pressure. A bicycle pump also works but takes longer for large adjustments.