The Basic Path: From Ground to Tap

A well pump moves water from underground up to your house by using an electric motor to create pressure or suction. The pump sits either inside the well itself (a submersible pump) or above ground next to it (a jet pump), and it pushes or pulls water through a pipe that runs into your home. The water then flows to a pressure tank, which stores it and keeps it ready whenever you turn on a faucet or shower.

The whole system works because of one straightforward fact: water is heavy, and lifting it 50 or 100 feet from the ground takes force. Your well pump provides that force. Without it, water would stay underground where gravity keeps it. With it, water reaches your kitchen sink.

Key Takeaways

  • A well pump uses an electric motor to push water up from underground through a pipe into your home's pressure tank.
  • Submersible pumps sit inside the well and work by pushing water upward; jet pumps sit above ground and work by creating suction.
  • A pressure tank stores water and maintains steady pressure so water flows smoothly when you open a faucet.
  • The pump turns on automatically when pressure in the tank drops below a set level and turns off when the tank reaches full pressure.
  • Most residential well pumps run on standard household electricity and last 8 to 15 years before needing replacement.

Submersible Pumps: Pushing Water From Inside the Well

A submersible pump sits underwater at the bottom of your well, sealed in a steel or plastic casing. The motor inside it spins an impeller—a wheel with curved blades—that forces water upward through a pipe. The deeper your well, the harder the pump has to work, so submersible pumps are rated by how many feet deep they can push water and how many gallons per minute they can move.

The pump is connected to the surface by an electrical cable that runs down the well pipe. When you turn on a faucet, the pressure in your tank drops, a pressure switch detects it, and electricity flows to the pump. The motor starts, the impeller spins, and water moves up the pipe. Once the tank fills and pressure rises to the set level (usually around 60 pounds per square inch), the switch cuts power and the pump stops.

Submersible pumps are common in deeper wells because they are efficient at lifting water long distances. They also stay cool because they are surrounded by water, so they rarely overheat. The trade-off is that if the pump fails, you have to pull it out of the well to repair or replace it, which takes time and equipment.

Jet Pumps: Pulling Water From Above Ground

A jet pump sits on the surface next to your well, usually in a basement or pump house. Instead of pushing water from below, it creates a vacuum—suction—that pulls water up through a pipe. Inside the pump, a motor spins an impeller that moves water fast enough to create low pressure, and that low pressure sucks water up from the well.

Jet pumps work well for shallow wells, typically those under 25 feet deep. They are easier to service because they are above ground and accessible. However, they are noisier than submersible pumps and less efficient at lifting water from deep wells. If your well is deeper than 25 feet, a jet pump will struggle and may not fill your tank reliably.

A jet pump needs a check valve in the well pipe to prevent water from flowing back down when the pump stops. Without it, the pump would lose its prime—the water that fills the pipe—and would have to refill every time it starts, which wastes energy and slows your water flow.

The Pressure Tank: Storing Water and Keeping Pressure Steady

The pressure tank is a metal or fiberglass container that stores water and air under pressure. When the pump fills the tank, water pushes against the air inside, building pressure. When you open a faucet, water flows out and pressure drops. Once pressure falls to the set minimum (often 40 psi), the pressure switch signals the pump to start again.

The tank serves two purposes. First, it stores water so the pump does not have to run every time you use a small amount of water—turning on a faucet for 10 seconds does not trigger the pump if the tank has enough reserve. Second, it maintains steady pressure so water flows smoothly instead of surging or trickling. Without a pressure tank, the pump would start and stop constantly, wearing out faster and creating pressure spikes that can damage pipes and fixtures.

Most residential tanks hold 20 to 80 gallons. A larger tank means the pump runs less often, which extends its life. A smaller tank means the pump cycles more frequently. The right size depends on your household's water use and how deep your well is.

How the Pressure Switch Controls the Pump

A pressure switch is a straightforward electrical device that turns the pump on and off automatically. It has two settings: a cut-in pressure (when the pump starts) and a cut-out pressure (when the pump stops). The difference between these two is called the pressure differential, usually 20 psi.

For example, if your switch is set to cut in at 40 psi and cut out at 60 psi, here is what happens: you use water, pressure drops to 40 psi, the switch closes an electrical contact, and the pump starts. Water fills the tank, pressure rises, and when it reaches 60 psi, the switch opens the contact and the pump stops. The next time you use water and pressure falls to 40 psi again, the cycle repeats.

If the pressure differential is too small, the pump will cycle on and off rapidly, which wears it out. If it is too large, you may notice weak water pressure at the tap because the tank has emptied more before the pump restarts. Most homeowners leave the factory settings alone unless they notice a problem.

Electrical Power and Safety Features

Well pumps run on standard household electricity, usually 120 or 240 volts depending on the pump size. The pump is wired through a dedicated circuit breaker so it does not share power with other appliances. A large pump may need its own 240-volt line to avoid overloading the house panel.

Most pumps have a thermal overload protector that cuts power if the motor gets too hot. This prevents the motor from burning out if the pump runs dry (no water in the well) or if something blocks the intake. If the overload trips, the pump stops and cools down. Once it cools, you can restart it, but you should find out why it overheated—usually a low water level or a clogged intake screen.

A check valve in the discharge line (the pipe leaving the pump) prevents water from flowing backward when the pump stops. Without it, water would drain back into the well, and the pump would lose pressure. Some systems also have a relief valve that opens if pressure gets too high, protecting pipes and fixtures from damage.

Common Problems and What Causes Them

If your pump is not delivering water, the problem is usually one of three things. First, the pump may have lost its prime—the water that fills the intake pipe. This happens most often with jet pumps and can be fixed by opening a priming plug and pouring water into the pump until it is full. Second, the intake screen at the bottom of the well may be clogged with sand or sediment, blocking water flow. Third, the pressure switch may be stuck or the electrical connection may be loose.

If the pump cycles on and off rapidly (more than once per minute), the pressure tank may be waterlogged—filled with too much water and not enough air. This reduces the tank's ability to cushion pressure changes. You can fix it by draining the tank, adding air with a bicycle pump or compressor, and refilling it. If the problem persists, the tank's internal bladder may have failed and the tank needs replacement.

If water pressure is weak, check whether the pressure switch is set too low. If it is set correctly, the problem may be a partially clogged intake screen, a leaking pipe, or sediment in the pressure tank. Sediment can be flushed out by opening the drain valve at the bottom of the tank and letting water run until it runs clear.

How Long a Well Pump Lasts and When to Replace It

A well pump typically lasts 8 to 15 years, depending on water quality, how often it cycles, and how well it is maintained. Pumps in areas with hard water or sandy wells wear out faster because minerals and sediment damage the impeller. Pumps that cycle constantly because the pressure tank is too small also wear out sooner.

You can extend a pump's life by flushing the pressure tank once a year to remove sediment, keeping the intake screen clean, and making sure the electrical connection is tight and dry. If you notice the pump running longer to fill the tank, or if it is cycling more frequently than it used to, the pump may be losing efficiency and replacement may be coming soon.

When a pump fails, you will notice no water at the tap or very weak pressure. If the pump is under warranty, contact the installer or manufacturer. If it is out of warranty, a replacement pump and installation typically costs between $1,000 and $3,000 for a submersible pump, depending on well depth and local labor rates. A jet pump replacement is usually less expensive because the pump itself is cheaper and easier to install.

Frequently Asked Questions

Can a well pump run out of water?

Yes, if the water table drops below the intake pipe. This happens during droughts or in areas where groundwater is being pumped faster than it recharges. If your pump starts sucking air, the thermal overload will trip and shut it down to protect the motor. You will need to wait for water levels to recover or have the intake pipe lowered deeper into the well.

Why does my well pump make noise?

Submersible pumps are usually quiet, but jet pumps are naturally loud because the impeller spins fast. If a submersible pump suddenly becomes noisy, it may be cavitating—creating air bubbles as it pulls water—which means the intake is partially blocked or the water level is dropping. Shut off the pump and check the intake screen.

Do I need to do anything to maintain my well pump?

Flush the pressure tank once a year to remove sediment, check that the electrical connection is dry and tight, and listen for unusual sounds or rapid cycling. If you have a jet pump, make sure the priming plug is accessible in case you need to refill it. Beyond that, most pumps need no regular maintenance until they fail.

What is the difference between a 1-horsepower pump and a 2-horsepower pump?

A larger horsepower rating means the pump can move more water per minute and lift it from greater depths. A 1 hp pump is fine for a household of four with a shallow well; a 2 hp pump is needed for deeper wells or larger households. The pump size should match your well depth and household water demand—oversizing wastes electricity, and undersizing means slow water pressure.

Can I install a well pump myself?

Installing a submersible pump requires pulling the old pump out of the well, which needs special equipment and experience. Installing a jet pump is simpler but still requires understanding plumbing connections, electrical wiring, and pressure switch settings. Most homeowners hire a licensed well contractor to do the work, which ensures the pump is sized correctly and installed safely.