Pressure Tank Basics

What does a pressure tank do?

A pressure tank stores pressurized water so the pump does not have to start every time a tap is opened. Inside, a cushion of air or a flexible barrier presses on the water. As you use water, the pressure drops to a set point and the pump starts, refilling the tank until a higher set point turns the pump off.

That cycle protects the pump. Frequent short starts wear the motor and the switch, so a healthy tank saves money and extends equipment life.

Pressure settings are chosen to suit the pump, the tank and the plumbing in the house. Changing one without the others can cause short cycling or low pressure, so treat the settings as a package and ask a professional before adjusting any of them.

What types of tanks exist?

Common designs include a diaphragm or bladder tank, where a flexible barrier separates air from water, and older plain steel tanks that rely on trapped air. Each needs different care. A bladder tank has an air charge that needs occasional checking, while an older tank may become waterlogged when its air cushion is lost.

Check the label on the tank for its type, size and maximum pressure. If the label is gone, ask a well contractor to identify it.

How do I know if my tank is failing?

Warning signs include a pump that turns on and off rapidly, pressure that swings up and down, sputtering faucets, water that lasts only a moment before the pump starts, and visible rust or leaks at the tank. A tank that feels waterlogged or heavy when tapped may have lost its air charge or its internal barrier.

Treat these as signs to call someone, not to experiment. Tanks hold pressure, and incorrect handling can injure you.

• Rapid cycling of the pump.
• Pressure that swings widely.
• Rust, leaks or bulging on the tank body.
• Sputtering water at the tap.

What maintenance is appropriate?

Keep the area around the tank dry and clear. Look over fittings and the base for moisture, and read the pressure gauge regularly, noting normal readings in your log. Many manufacturers advise checking the air charge once or twice a year, but the exact steps depend on the model and require turning off power and relieving pressure, so follow the manual or hire a technician.

Never adjust the pressure switch or open the tank without knowing the procedure. Wrong settings can damage the pump and create a safety risk.

How is a tank sized and replaced?

Tank size relates to pump capacity, household demand and how much water you want available between pump starts. A well professional can recommend a size and pressure range suited to your pump and plumbing. Bigger is not always better, and the tank must match the system's pressure settings.

When replacing a tank, ask what permits and inspections apply. Rules differ by state and county, and many places require licensed work on well systems. Budget for the tank, fittings, labor and any related switch or gauge replacement.

If your household changes, such as new animals, a larger garden or added bathrooms, ask whether the tank and pump still fit. Demand grows quietly, and a system that was right years ago may now be working too hard.

What should I do before a tank problem becomes an emergency?

Know where to switch off power and water, store emergency drinking water, and keep your well contractor's number handy. If you see a tank leaking heavily, bulging or hissing, keep people away, shut off power only if it is safe to reach the breaker, and call a professional right away.

After the repair, record the date, settings and any parts replaced. Next time, you will start with better information.

What questions should I ask a well contractor?

Ask what type of tank you have, how old it is, what pressure range the system is set to and whether the pump and switch match the tank. Ask what signs of failure to watch for and how often to have the system checked. A good contractor will explain in plain words and write down the details for your records.

Ask whether the tank is the right size for your household and animals, and whether you would benefit from a different setup. Ask about permits, warranties and what the quote includes, including disposal of the old tank.

Finally, ask what to do in an emergency. Knowing where to turn off power and water, and who to call after hours, makes a leak or burst less frightening. Keep the answers with your system records.

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.