The Basic Path: How Water Moves From Below Ground to Your Home

A water well pump pulls water from underground and pushes it up to your house. The pump sits either inside the well (submersible) or above ground (jet pump), and it works by creating a pressure difference—lower pressure below the water surface, higher pressure in the pipe leading to your home. This pressure difference forces water upward against gravity, sometimes from depths of 25 feet or deeper.

The pump itself is powered by an electric motor. When you turn on a faucet, a pressure switch inside your home's tank senses that pressure has dropped, and it signals the motor to start. The motor spins an internal mechanism that either pushes water directly (like a piston) or spins an impeller (a fan-like wheel) that flings water outward and upward into the discharge pipe.

Key Takeaways

  • A well pump creates pressure to force water from underground into your home's pipes, working against gravity and distance.
  • Submersible pumps sit inside the well and are most common for deep wells; jet pumps sit above ground and work better for shallow wells.
  • An electric motor powers the pump, and a pressure switch automatically turns it on when water pressure drops below a set level.
  • The pump fills a pressure tank in your home, which stores water and reduces how often the pump needs to run.
  • Common problems include air in the lines, a failed pressure switch, or a motor that won't start—all fixable without replacing the whole pump.

Submersible Pumps: The Pump Inside the Well

A submersible pump is sealed in a metal or plastic housing and lowered into the well on a pipe and electrical cable. It sits underwater, usually 20 to 100 feet below the surface. Because it is submerged, it can pull water from much deeper than a pump sitting above ground—the water pressure around it helps push water into the pump intake.

Inside, an electric motor turns a series of impellers stacked on top of each other. Each impeller is a small fan-shaped wheel. As the motor spins, each impeller flings water outward and upward into the next stage, like a relay race. By the time water reaches the top of the pump, it has been pushed hard enough to travel up the discharge pipe, through your home's pressure tank, and into your pipes at usable pressure (usually 40 to 60 pounds per square inch).

Submersible pumps are sealed against water, so they do not leak, and they run quietly because they are underwater. The main drawback is that if one fails, you have to pull it out of the well to repair or replace it—a job that usually requires a professional and specialized equipment.

Jet Pumps: The Pump Above Ground

A jet pump sits in a basement, garage, or pump house above ground. It uses a different method: it sends a small amount of water down into the well through a jet nozzle, which creates a low-pressure zone. This low pressure sucks water up from the well into a second pipe, where it mixes with the pressurized water and gets pushed into your home's tank.

Jet pumps work well for shallow wells (under 25 feet deep) because they rely on atmospheric pressure to help pull water up, and atmospheric pressure weakens with depth. For deeper wells, a deep-well jet pump uses two pipes instead of one—the jet nozzle and the water return are both in the well, which reduces the distance the pump has to pull water.

Jet pumps are easier to access and repair than submersible pumps because they sit above ground. However, they are louder, they can lose their prime (the water seal that lets them work), and they are less efficient for very deep wells.

The Pressure Tank: Why Your Pump Does Not Run Constantly

Your home has a pressure tank—a metal or plastic tank, usually in the basement or utility room, that stores pressurized water. When the pump runs, it fills this tank until pressure reaches a set level (often 60 pounds per square inch). A pressure switch inside the tank senses when pressure drops below a lower set point (often 40 psi), and it signals the pump motor to start again.

Without a pressure tank, the pump would turn on and off dozens of times a day every time you used water. The tank acts as a buffer, holding enough water so that small uses (a toilet flush, a quick hand wash) do not trigger the pump. This saves wear on the motor and reduces your electric bill. The tank also smooths out pressure spikes that could damage pipes and fixtures.

Over time, the air cushion inside the tank can shrink, and the tank can become waterlogged. If you notice the pump running more often than usual, or if pressure fluctuates wildly, the tank may need air added back in or may need replacement.

The Pressure Switch and Electrical Control

The pressure switch is a small device screwed onto the pressure tank or the pump discharge line. It contains a spring-loaded piston that moves as pressure changes. When pressure drops below the "cut-in" point (usually 40 psi), the piston moves and closes an electrical contact, sending power to the pump motor. When pressure rises above the "cut-out" point (usually 60 psi), the piston moves back and opens the contact, shutting the motor off.

The switch also has a manual lever or button that lets you turn the pump on or off by hand—useful for troubleshooting or maintenance. If the switch fails, the pump may run constantly, not run at all, or cycle on and off rapidly. A failed switch is one of the most common well pump problems and is usually cheaper to replace than the pump itself.

Some modern systems use a variable-frequency drive (VFD) instead of a straightforward on-off switch. A VFD adjusts the motor speed continuously to match water demand, which saves energy and reduces wear on the pump.

How Water Reaches Your Taps: From Tank to Faucet

Once water is in the pressure tank, it stays there under pressure. When you open a faucet, water flows out because the pressure in the tank pushes it through your home's pipes. As water leaves, pressure inside the tank drops. When it falls below the cut-in point, the pressure switch signals the pump to start and refill the tank.

The water path is: pump discharge → pressure tank → main water line → branch pipes to each faucet, toilet, and appliance. Some homes have a check valve (a one-way valve) between the pump and the tank to prevent water from flowing backward into the well when the pump stops. Others have a foot valve at the bottom of the intake pipe inside the well, which serves the same purpose.

If you notice low pressure at your taps, the problem could be a clogged intake screen, a failed check valve, a leak in the discharge pipe, or sediment inside the pump itself. A professional can test pressure at different points to pinpoint where the problem is.

Common Problems and What They Mean

If your pump runs constantly, the pressure switch may be stuck, the tank may be waterlogged, or there may be a leak in the discharge line. A small leak can waste hundreds of gallons before you notice it. Check for wet spots around the tank and pipes, and listen for a hissing sound near the pressure switch.

If the pump will not start at all, check that power is reaching it (look for a tripped circuit breaker or a blown fuse). If power is on but the motor does not turn, the motor may be burned out, or the pump may be jammed by sediment or debris. If the pump starts but produces no water, the intake may be clogged, the check valve may be stuck, or the pump may have lost its prime.

Air in the discharge line causes sputtering at the taps and can damage the pump over time. This usually happens after the pump has been off for a while or after maintenance. Running the pump for a few minutes usually clears the air, but if it persists, there may be a leak in the intake line that is letting air in.

Frequently Asked Questions

How deep can a well pump pull water from?

A submersible pump can pull water from 300 feet or deeper because it sits in the water. A jet pump can pull from about 25 feet; a deep-well jet pump can reach 50 feet. Depth depends on the pump model, the power of the motor, and the water table in your area. A well driller can tell you the depth of your well and recommend the right pump type.

Why does my pump cycle on and off so much?

Frequent cycling usually means the pressure tank is waterlogged or the pressure switch is set too close to the cut-in and cut-out points. It can also mean a small leak is slowly draining the tank. Have the tank pressure tested and the switch settings checked. If the tank is waterlogged, it may need air added or replacement.

What happens if the pump loses power during a storm?

The water in your pressure tank will stay pressurized for a few hours, so you can still use water. Once the tank pressure drops below the cut-in point, no more water will flow. A backup generator can keep the pump running during an outage, or you can store water in containers beforehand.

How often should a well pump be serviced?

Most pumps do not need routine maintenance, but the pressure tank should be checked every few years to make sure it has the right air pressure. The pump intake screen should be inspected if water quality drops. A professional inspection every 5 to 10 years can catch problems early and extend the pump's life.

Can I replace a submersible pump myself?

Pulling a submersible pump out of a well requires a tripod or winch and careful handling of the electrical cable. Most homeowners hire a well contractor for this job. If you have a jet pump above ground, you may be able to replace it yourself if you are comfortable with plumbing and electrical work, but a professional installation is safer and usually comes with a warranty.