What causes low pressure in a well and how to fix it

Low water pressure in a well system usually comes from one of four places: a failing pressure tank, a clogged intake line, sediment in the well itself, or a pump that is losing power. The fastest fix is often the simplest — check your pressure tank first, because a waterlogged tank (one filled with water instead of air) stops pressure from building at all. If the tank is the problem, you can drain it and restore the air charge in under an hour. If not, the issue is likely in the well line, the pump, or the well screen, and each requires a different approach.

Before you call a well contractor, you can test which part is failing by checking pressure at different points in your system. A pressure gauge on the tank tells you what the pump is actually producing. Low gauge readings mean the pump itself is weak. Normal gauge readings with weak flow at your faucets mean the problem is between the tank and your house — usually a clogged line or sediment trap.

Key Takeaways

  • A waterlogged pressure tank is the most common cause of low pressure and can be fixed by draining the tank and restoring the air bladder.
  • A pressure gauge on your tank costs under $20 and tells you whether the pump or the plumbing is the problem.
  • Sediment in the well screen or intake line can be cleared by backflushing or by having the well professionally cleaned.
  • If the pump itself is weak, it may need to be rebuilt or replaced, which usually requires a well contractor.
  • Pressure tank air charge should be checked every few years, because the bladder inside slowly loses air over time.

How to drain and recharge your pressure tank

Start by turning off the pump at the breaker or switch. Open a faucet somewhere in the house to release pressure from the tank — you will hear air hiss out. Once the hissing stops, the tank is empty.

Look at the top of the tank. You should see a small valve that looks like a tire valve on a car. Use a tire pressure gauge to check the air pressure inside. It should read about 2 pounds per square inch (PSI) below your pump's cut-in pressure — if your pump turns on at 40 PSI, the tank air should be around 38 PSI. If the gauge reads zero or very low, the air bladder inside the tank has failed and the tank needs to be replaced. If it reads something but is lower than it should be, you can add air.

Use an air compressor to pump air into that valve until the gauge reads the correct PSI. Do not overfill — too much air pressure will prevent the pump from turning on. Once you have set the air charge, close the valve, turn the pump back on, and check your water pressure at a faucet. Pressure should improve noticeably within a few minutes.

Clearing sediment and debris from the well line

Sediment in the intake line or well screen reduces flow even if the pump is working correctly. You can test for this by opening a faucet and watching the water. If it comes out cloudy or discolored at first, then clears, sediment is moving through the line. If it stays cloudy, the problem is deeper in the well.

The simplest fix is backflushing. Turn off the pump and locate the sediment trap — a small tank or chamber on the line between the well and your pressure tank. Open the drain valve at the bottom and let water run out for 30 seconds to a minute. This pushes sediment out of the trap. Close the valve, turn the pump back on, and test your pressure again.

If backflushing does not help, sediment may be clogged in the well screen itself. This requires either a professional well cleaning (which uses high-pressure water to flush the screen) or pulling the pump and screen out to clean them by hand. Well cleaning costs between $300 and $800 depending on the depth of your well and how much sediment has built up. It is worth doing if your pressure has dropped gradually over months or years.

Testing and replacing a failing pump

If your pressure gauge reads low (below 30 PSI on a system that should run at 40 PSI or higher), the pump itself is losing power. This usually means the pump motor is wearing out or the pump impeller (the spinning part that moves water) is damaged.

Before replacing the pump, confirm the problem is not electrical. Check that the breaker for the pump has not tripped and that the power switch is in the on position. If power is reaching the pump but pressure is still low, the pump needs to be rebuilt or replaced. A pump rebuild costs $400 to $800 and involves replacing internal seals and the impeller. A full pump replacement runs $1,200 to $2,500 depending on the pump size and your well depth. Most well contractors can do either job in a day.

When to call a well contractor

You should call a contractor if your pressure gauge reads low and stays low after you have recharged the pressure tank. You should also call if backflushing does not clear sediment, or if the water stays cloudy or discolored after flushing. A contractor can pull your pump and inspect the well screen, test the pump motor, and determine whether cleaning, repair, or replacement is needed.

Get at least two quotes before committing to work. A contractor should be able to tell you over the phone whether the problem is likely the pump, the screen, or something else, based on your description of when the pressure dropped and what the water looks like. Ask whether they charge a diagnostic fee — many do, and it is usually $100 to $200, but they will credit it toward the repair if you hire them.

Maintaining pressure to prevent future drops

Check your pressure tank air charge once a year, ideally in the fall before winter. A tire pressure gauge costs under $10 and takes 30 seconds to use. If the air charge is low, top it up before the tank loses pressure completely.

If you have a sediment trap, open the drain valve for 30 seconds every six months. This keeps sediment from building up in the trap and clogging your line. If your water is often cloudy or discolored, consider installing a sediment filter on the intake line — these cost $150 to $400 installed and catch particles before they reach your pressure tank or faucets.

Keep a record of when your pump was installed and when it was last serviced. Most submersible pumps last 15 to 25 years depending on water quality and how often they run. If yours is older than 20 years and pressure has dropped, replacement may be more cost-effective than repeated repairs.

Frequently Asked Questions

How do I know if my pressure tank is waterlogged?

A waterlogged tank feels heavy and full of water when you tap it, and the pump runs constantly even when no one is using water. The fastest test is to check the air valve at the top with a tire pressure gauge — if it reads zero, the bladder has failed. You can also turn off the pump and open a faucet; if water flows for only a few seconds before stopping, the tank is waterlogged.

Can low water pressure damage my pump?

No, but a pump running constantly because of a waterlogged tank will wear out faster. A pump that cycles on and off normally (every few minutes) lasts much longer than one that runs all day. If your pressure tank is failing, replacing it now is cheaper than replacing the pump later.

What PSI should my well pump be set to?

Most household well systems run between 40 and 60 PSI. The pump turns on when pressure drops to the cut-in point (usually 40 PSI) and turns off when it reaches the cut-out point (usually 60 PSI). Your pressure tank air charge should be about 2 PSI below the cut-in point. Check your pump manual or call your contractor to confirm the correct settings for your system.

Is it normal for well water to be cloudy sometimes?

Cloudy water that clears after a few seconds is usually air bubbles and is harmless. Cloudy water that stays cloudy or returns after a few days means sediment is in your line or well screen. Run the sediment trap drain valve and see if the water clears. If it does not, you may need professional well cleaning.

How much does it cost to have a well professionally cleaned?

Professional well cleaning typically costs $300 to $800 depending on well depth and how much sediment has built up. Shallow wells (under 100 feet) are usually cheaper than deep wells. Get a quote from your contractor before scheduling, as prices vary by region and the specific condition of your well.