Why your well pressure drops and how to restore it
Well water pressure falls when the pump stops pushing water hard enough to reach your taps, or when the pressure tank loses its air charge. The most common causes are a waterlogged pressure tank, a failing pump, a clogged intake line, or sediment blocking the well screen. Before you call a well contractor, you can check and fix several of these yourself—and knowing what's happening will save you money on the service call.
Pressure tanks store water under air pressure so your pump doesn't run every time you turn on a faucet. Over time, the air bladder inside the tank can fail, allowing water to fill the entire tank. When that happens, the pump has nowhere to push water, and pressure drops. This is the single most common reason for low pressure in a well system, and it's often fixable in an afternoon.
Key Takeaways
- A waterlogged pressure tank—where the air bladder has failed and water fills the whole tank—is the most common cause of low well pressure and can often be fixed by draining and recharging the tank yourself.
- Check your pressure gauge reading: if it's below 20 pounds per square inch (psi) when the pump is running, or if the pump cycles on and off constantly, the tank or pump needs attention.
- Sediment, mineral buildup, or debris in the intake line or well screen will reduce pressure gradually; flushing the system or replacing the screen may restore flow.
- If the pump itself has failed, pressure will drop suddenly and the pump may not run at all; this requires a well contractor to replace or repair the pump.
Check your pressure tank first
The pressure tank is the easiest place to start. Locate it near your well pump—it's usually a metal cylinder standing upright or lying on its side. Look for a pressure gauge mounted on top or on a nearby pipe. Write down the reading when the pump is running and when it has just shut off. A healthy system reads between 40 and 60 psi when the pump stops, and drops to around 20 psi before the pump kicks back on.
If the gauge reads very low (below 20 psi) or if the pump is turning on and off every few seconds, the tank is likely waterlogged. You can test this by tapping the tank with a wrench—a healthy tank sounds hollow in the upper half and solid in the lower half. A waterlogged tank sounds solid all the way up. If you hear water sloshing inside when you tap it, the air bladder has failed.
Draining and recharging the tank is straightforward. Turn off the pump at the breaker, open a faucet in the house to release pressure, then locate the drain valve at the bottom of the tank and open it to let all water out. Once empty, use an air compressor to pump air into the air valve (usually a small fitting on top, similar to a car tire valve) until the gauge reads 2 psi below your pump's cut-in pressure—typically 38 psi if your pump is set to stop at 40 psi. Close the drain valve, turn the pump back on, and let it refill the tank. The pressure should now climb to your normal range.
Look for leaks and blockages in the supply line
If the tank is holding pressure but flow is still weak, the problem is likely between the well and the tank. Sediment, mineral deposits, or debris can clog the intake line or the well screen—the filter at the bottom of the well that keeps sand out of your pump.
Start by checking for visible leaks around the well cap, pump connections, and any exposed pipe. A slow drip or wet soil around the wellhead means water is escaping before it reaches your house. Small leaks can be tightened at the fitting; larger ones may require a plumber. If you see no leaks, the blockage is likely inside the line or screen.
You can flush the system yourself by opening the lowest faucet in your house (usually a basement or outdoor spigot) and letting water run hard for several minutes. This can dislodge loose sediment. If pressure doesn't improve, the well screen may need professional cleaning or replacement. A well contractor can pull the pump and inspect the screen, or use a jetting service to clear the intake line. This is a job to call a professional for, as it requires opening the well and handling the pump safely.
Test the pump itself
If the pressure tank is charged correctly and the supply line is clear, the pump may be failing. A pump that has lost power will not run at all; a pump that is wearing out will run but deliver weak pressure.
Listen for the pump motor running when you turn on a faucet. You should hear it hum and feel a slight vibration. If the motor doesn't run, check the breaker—it may have tripped. If the breaker is on and the motor still won't start, the pump has likely failed and needs replacement. If the motor runs but pressure is still low, the pump's internal impeller may be worn or damaged, which also requires replacement.
Pump replacement is not a DIY job. The pump sits at the bottom of the well, and pulling it requires specialized equipment and knowledge of well safety. Call a licensed well contractor to diagnose and replace a failing pump. They will also check the pressure switch—the device that tells the pump when to turn on and off—which can sometimes be adjusted or replaced instead of the pump itself.
Adjust or replace the pressure switch
The pressure switch is a small box mounted on the pipe near the pressure tank. It turns the pump on when pressure drops below a set point (usually 20 psi) and off when pressure reaches the cut-off point (usually 40 psi). If the switch is stuck or miscalibrated, the pump may not run at all, or may run constantly without building pressure.
You can check the switch by listening for a click when you turn on a faucet and the pressure drops. If you hear no click, the switch may be stuck. Do not try to adjust it yourself—pressure switches are calibrated to your specific system, and incorrect adjustment can damage the pump or create unsafe pressure. A well contractor can test the switch with a multimeter and adjust or replace it if needed.
When to call a well contractor
Call a professional if any of the following explore: the pump doesn't run at all; pressure drops suddenly rather than gradually; you see water pooling around the wellhead; the pressure switch doesn't click when you turn on a faucet; or you've drained and recharged the pressure tank and pressure still hasn't improved.
A well contractor will bring a pressure gauge, multimeter, and tools to pull the pump if needed. They can diagnose whether the problem is the pump, the pressure switch, the well screen, or the supply line. The cost of a service call is usually between $150 and $300, but catching a failing pump early can save you from a complete system failure that costs thousands to repair.
If you live in an area with hard water or high mineral content, ask the contractor about installing a sediment filter on the intake line. This can prevent future blockages and extend the life of your pump.
Frequently Asked Questions
Can low water pressure damage my pump?
No, but a pump running constantly because the pressure tank is waterlogged will wear out faster. The pump is designed to cycle on and off; if it runs without stopping, the motor overheats and fails sooner. Fixing a waterlogged tank quickly protects the pump.
What's the difference between low pressure and low flow?
Pressure is the force pushing water through your pipes; flow is the amount of water coming out. Low pressure means weak spray from a faucet. Low flow means water comes out slowly but with normal force. Low pressure usually points to the tank or pump; low flow usually points to a blockage in the supply line or well screen.
Is it safe to drain the pressure tank myself?
Yes, as long as you turn off the pump first and release the pressure by opening a faucet. The tank holds water under pressure, so opening the drain valve without releasing pressure first can cause a sudden spray. Always turn off the pump at the breaker before you start.
How often should I recharge the pressure tank?
A healthy tank should hold its air charge for years. If you're recharging it more than once a year, the air bladder is failing and the tank needs replacement. Constant recharging means you're fighting a losing battle; a new tank costs $300 to $800 and will serve you for 10 to 15 years.
Will a water softener help with low pressure?
No. A water softener treats mineral content in the water but doesn't affect pressure. If mineral buildup is clogging your well screen, a softener won't clear the existing blockage—you'll need the screen cleaned first. After that, a softener can slow future mineral deposits.