Why well water pressure drops and what you can do about it

Well water pressure falls when the pump loses power, the pressure tank fails, sediment clogs the system, or the well itself runs dry during heavy use. You can often restore it by checking the pressure tank air charge, cleaning or replacing the pressure switch, flushing sediment from the line, or having a well service inspect the pump and tank. Some fixes take an hour and cost nothing; others require a technician and run several hundred dollars.

The pressure tank is the first place to look because it fails more often than anything else and is the cheapest to fix. If the tank has lost its air charge, the pump will cycle on and off constantly and deliver weak pressure. A well service can recharge it in under an hour. If the tank itself is rusted or waterlogged, replacement costs between $500 and $1,500 depending on size.

Key Takeaways

  • Check the pressure tank air charge first — a tank that has lost pressure will cause weak flow and constant pump cycling, and recharging costs under $100.
  • Sediment buildup in the pressure tank or supply line reduces flow and can be flushed out, though heavy buildup may require tank replacement.
  • A failed pressure switch prevents the pump from turning on or keeps it running constantly, and replacement costs $150 to $300.
  • If pressure is low throughout the house but the well pump runs normally, the well itself may be running dry or the pump may be undersized for your household demand.
  • A well service inspection costs $150 to $300 and can identify whether the problem is the pump, tank, switch, or well capacity.

Check and recharge the pressure tank

The pressure tank holds pressurized air that pushes water through your house when the pump is off. Over time, the air charge leaks out, and the tank fills with water instead. When this happens, the pump turns on and off constantly and delivers only weak pressure.

To check the air charge, turn off the pump at the breaker and drain the tank by opening a faucet. Locate the air valve on top of the tank — it looks like a tire valve. Use a tire pressure gauge to check the reading. The air pressure should be about 2 pounds per square inch (psi) below your system's cut-in pressure. If your pump turns on at 40 psi, the air charge should read around 38 psi. If it reads zero or very low, the charge has leaked out.

You can recharge the tank yourself using an air compressor and a tire pump, or call a well service to do it. Turn the pump back on after recharging. If the pressure holds for a week or more, the tank is fine. If it drops again within days, the tank has a leak and needs replacement.

Clean or replace the pressure switch

The pressure switch tells the pump when to turn on and off. When it fails, the pump may not run at all, or it may run constantly without building pressure. A stuck or corroded switch is a common cause of low pressure.

The switch is a small box mounted on the pipe near the pressure tank. Turn off the pump and remove the cover. If you see corrosion or mineral buildup inside, you can try cleaning the contacts with a dry cloth or fine sandpaper. Turn the pump back on and check the pressure. If cleaning does not work, or if the switch is cracked, it needs replacement.

A new pressure switch costs $40 to $80 for the part, but installation requires turning off the pump and draining the system. Many homeowners hire a well service for this job, which adds $150 to $200 in labor. If you are comfortable working with plumbing, you can do it yourself by following the manufacturer's instructions for your specific switch model.

Flush sediment from the tank and supply line

Sand, silt, and mineral deposits accumulate in the pressure tank and supply line over time, especially in older wells. This buildup narrows the passages water travels through and reduces flow to every faucet in the house.

To flush the tank, turn off the pump and close the isolation valve between the tank and the house. Open the drain valve at the bottom of the tank and let water run until it runs clear. This may take 15 to 30 minutes. Close the drain valve, reopen the isolation valve, and turn the pump back on.

If flushing the tank does not improve pressure, sediment may be stuck in the supply line itself. A well service can flush the entire system using high-pressure water or compressed air. This service costs $200 to $400. If sediment is very heavy, the tank may need replacement because the buildup cannot be fully removed.

Inspect the well pump and capacity

If pressure is low but the pump runs normally and the tank and switch are in good condition, the pump itself may be failing or undersized. A pump that is too small for your household cannot keep up with demand during peak use — morning showers, laundry, and watering the yard all at once.

A well service can test the pump's output by measuring how many gallons per minute it delivers. Most household wells produce between 5 and 15 gallons per minute. If your pump delivers less than 3 gallons per minute, it is either failing or undersized. Replacement pumps cost $800 to $2,000 installed, depending on well depth and pump type.

The well itself may also be running dry. This happens during drought or when household demand exceeds the well's recharge rate. A well service can measure the water level in the well to determine if this is the problem. If the well is running dry, you may need to drill deeper, install a larger storage tank, or reduce peak demand by staggering water use.

When to call a well service versus doing it yourself

Recharging the pressure tank and cleaning the pressure switch are jobs most homeowners can do with basic tools and a tire pressure gauge. Flushing the tank requires only a wrench and takes less than an hour. These three steps cost under $50 in parts and no labor.

Replacing the pressure switch, flushing the supply line, or inspecting the pump require more skill and specialized equipment. A well service visit costs $150 to $300 for diagnosis alone, but the technician can identify the exact problem and quote repair costs before you commit. If the pump needs replacement or the well is running dry, a professional assessment is worth the cost because the wrong fix wastes money.

Start with the pressure tank and switch yourself. If pressure improves, you have solved the problem for under $50. If it does not, call a well service. They can test the pump output, measure the water level, and inspect the tank for rust or leaks in one visit.

Frequently Asked Questions

How do I know if my pressure tank is waterlogged?

A waterlogged tank feels heavy and full when you shake it, and the pump cycles on and off constantly even after you recharge the air. The tank will not hold pressure for more than a few hours. Replacement is the only fix, and it costs $500 to $1,500 depending on tank size.

Can low water pressure be caused by a clogged well screen?

Yes. The well screen at the bottom of the well can become clogged with sediment or mineral buildup over decades. A well service can test for this by measuring water level and pump output. If the well is producing very little water, the screen may need cleaning or the well may need to be redeveloped, which costs $500 to $1,500.

What is the normal water pressure for a well system?

Most well systems run between 40 and 60 psi. The pump turns on at the lower number and shuts off at the higher number. If your pressure gauge reads below 30 psi, something is wrong. If it reads above 80 psi, the pressure relief valve may be stuck or the tank may be oversized.

Will increasing the pressure switch setting give me more water pressure?

Adjusting the switch can raise the pressure slightly, but it will not fix the underlying problem. If the pump cannot deliver water fast enough, raising the pressure setting will only make the pump run longer and wear out faster. Have a well service test the pump output before adjusting the switch.

How often should a pressure tank be replaced?

A well-maintained pressure tank lasts 10 to 15 years. Tanks in areas with hard water or high mineral content fail sooner because sediment builds up inside. If your tank is older than 10 years and pressure is dropping, replacement is often cheaper than repeated repairs.