What causes low well water pressure and how to restore it

Low well water pressure usually comes from one of four sources: a failing pressure tank, a clogged intake line, sediment buildup in your pipes, or a pump that is losing power. The fastest way to find out which one is your problem is to check your pressure gauge — most wells have one mounted on the tank or near the pump. If the gauge reads below 40 pounds per square inch (psi), your system is underperforming. Start by checking whether the tank is waterlogged, because that is the most common cause and the easiest to fix yourself.

Before you call a well contractor, you can rule out several problems in under an hour. A waterlogged tank, a tripped breaker on the pump, or a closed valve between the well and your house are all things you can spot and often fix without a service call. If none of those are the issue, you will need to know what to tell the contractor so they can bring the right equipment.

Key Takeaways

  • A waterlogged pressure tank — one that has lost its air charge — is the most common cause of low pressure and can often be fixed by draining and recharging it yourself.
  • Check that the pump's circuit breaker has not tripped and that the valve between the well and your house is fully open before assuming the pump has failed.
  • Sediment in your well water clogs screens and reduces flow; a whole-house sediment filter can slow this buildup, but a failing well screen usually requires professional replacement.
  • Pressure tanks typically last 10 to 15 years; if yours is older and recharging does not restore pressure, replacement is usually cheaper than repair.
  • A well pump that has lost prime — stopped being able to draw water — usually needs a contractor to diagnose, because the cause can be a leak, a failed check valve, or a drop in the water table.

How to check and recharge a waterlogged pressure tank

A pressure tank stores water under air pressure so that your pump does not run every time you turn on a faucet. Over time, the air bladder inside the tank can rupture or the air charge can leak out, leaving the tank full of water but no air to push it. When this happens, pressure drops and the pump runs constantly. You can test this by turning off the pump and tapping on the tank with your knuckles — a waterlogged tank sounds hollow and dull, while a healthy tank with air inside sounds more resonant.

To recharge the tank yourself, you will need an air compressor and a tire gauge. First, turn off the pump at the breaker. Locate the air valve on top of the tank — it looks like a bicycle tire valve. Use the tire gauge to check the current pressure; it should be about 2 psi below your system's cut-in pressure (usually around 38 psi for a system that cuts in at 40 psi). If the reading is zero or very low, use the air compressor to add air until you reach the target pressure. Then turn the pump back on and check your water pressure at a faucet. If pressure improves, the tank was the problem. If pressure is still low, move to the next step.

If recharging does not work, the tank's internal bladder has likely failed and the tank needs replacement. A new pressure tank costs between $300 and $800 installed, depending on size and your region. Repair is rarely worth the cost.

Check the pump breaker and the isolation valve

Before you assume the pump itself is broken, verify that it is actually running. Go to your electrical panel and look for the breaker labeled for the well pump — it is usually a double-pole breaker. If it is in the OFF position or in the middle (tripped), switch it fully to ON. Wait a few minutes for the pump to build pressure, then check a faucet. If water pressure returns to normal, the breaker had straightforward tripped, possibly from a power surge or an overload.

Next, locate the isolation valve between the well and your house — it is usually near the pressure tank or where the well line enters the house. It should be a ball valve with a handle. Make sure the handle is parallel to the pipe (meaning the valve is open). If the handle is perpendicular to the pipe, the valve is closed and no water can flow. Turn it parallel and check your pressure again. These two checks take five minutes and solve the problem in roughly one out of every ten low-pressure calls.

Flush sediment from your well system

Sediment — sand, silt, and mineral particles — accumulates in well water over time and clogs the small openings in your pump intake, pressure tank, and faucet screens. If your water pressure has dropped gradually over months rather than suddenly, sediment is likely the cause. You can slow this buildup by installing a whole-house sediment filter on the line between the well and your pressure tank. These filters cost $150 to $400 and need cartridge replacement every 6 to 12 months depending on how much sediment your well produces.

To flush sediment from your system, turn off the pump and locate the drain valve at the bottom of the pressure tank. Attach a garden hose and open the valve to drain the tank completely. Then turn the pump back on and let it run for several minutes while water flows out the hose — this flushes sediment from the tank. Close the drain valve, refill the tank, and check your pressure. This is a temporary fix; the sediment will return unless you install a filter.

If sediment is heavy enough that flushing does not help, your well screen may be failing. A well screen is a mesh barrier at the bottom of the well that keeps sand out of the pump. When it clogs or tears, sediment floods the system and pressure drops sharply. Replacing a well screen requires pulling the pump and dropping a new screen down the well — this is a job for a licensed well contractor and typically costs $500 to $1,500.

Test whether the pump has lost prime

A pump loses prime when air enters the intake line and breaks the seal that allows the pump to draw water up from the well. When this happens, the pump runs but no water comes out, or pressure is extremely low. You can test for this by opening a faucet and listening — a pump that has lost prime usually makes a grinding or squealing noise and produces little or no water.

A lost prime can be caused by a leak in the intake line, a failed check valve (a one-way valve that prevents water from flowing backward), or a drop in the water table if your well is shallow. Some of these you can spot: look for wet soil around the well head or along the line from the well to the house, which indicates a leak. If you see no obvious leak and the pump is making noise but producing no water, the check valve or the water table is likely the problem. Both of these require a contractor to diagnose and fix.

When to call a well contractor

If you have checked the pressure tank, the breaker, the isolation valve, and flushed sediment but pressure is still low, a contractor needs to test the pump itself. They will measure the pump's output in gallons per minute and check whether it is producing the flow rate it should for your well depth. They can also test the check valve and the intake line for leaks. A service call typically costs $150 to $300 for diagnosis; repair or replacement costs vary widely depending on what they find.

Well pumps last 8 to 15 years depending on use and water quality. If your pump is older than 12 years and pressure has been dropping gradually, replacement is often more cost-effective than repair. A new submersible pump and installation typically runs $1,500 to $3,000. Ask the contractor whether your well has a history of low water table issues in your area — if it does, a deeper well or a larger storage tank may be necessary.

Install a sediment filter to prevent future pressure loss

Once you have restored your pressure, a whole-house sediment filter will protect your system from the most common cause of gradual pressure loss. These filters sit between the well and the pressure tank and catch particles before they reach your pump and pipes. A 20-micron filter catches most sand and silt; a 5-micron filter catches finer sediment but clogs faster and needs more frequent cartridge changes.

Filter cartridges cost $20 to $60 each and typically need replacement every 6 to 12 months, depending on your well water quality. You can check whether a cartridge needs changing by looking at the pressure gauge on the filter housing — if it reads more than 10 psi higher than your system pressure, the cartridge is clogged and should be replaced. Installing a filter does not fix a failing well screen, but it does extend the life of your pump and pressure tank by keeping sediment out of the system.

Frequently Asked Questions

How do I know if my pressure tank is waterlogged?

Tap the tank with your knuckles — a waterlogged tank sounds dull and hollow, while a healthy tank sounds more resonant. You can also check the air valve on top with a tire gauge; if it reads zero or very low psi, the tank has lost its air charge. A waterlogged tank usually causes pressure to drop suddenly rather than gradually.

Can low well pressure damage my pump?

Yes. A pump that runs constantly because pressure is not building will overheat and wear out faster. A waterlogged tank or a clogged filter forces the pump to work harder than it should. Fixing low pressure quickly extends the life of your pump and reduces your electric bill.

What is the difference between a sediment filter and a water softener?

A sediment filter removes particles like sand and silt that cloud water and clog pipes. A water softener removes minerals like calcium and magnesium that make water hard. You can have both — the sediment filter usually comes first, right after the well, to protect the softener from clogging.

Why does my pressure drop only when I use hot water?

Hot water lines are smaller than cold water lines in most houses, so they clog faster with sediment. If pressure is normal for cold water but low for hot, a sediment filter on the hot water line or a whole-house filter before the water heater will help. You may also need to flush sediment from the water heater itself.

How often should I have my well inspected?

Most well contractors recommend an inspection every 3 to 5 years, or sooner if you notice changes in water pressure, flow, or clarity. An inspection typically includes testing pressure, flow rate, and water quality. If your well is older than 20 years, annual inspection is a good idea because components are more likely to fail.