What a well pump does and where it sits
A well pump pulls water from underground and pushes it into your home's pipes. The pump sits either inside the well itself (submerged below the water table) or above ground next to the well, depending on how deep your water is. Most residential wells are between 25 and 300 feet deep, and the pump's job is always the same: overcome the distance and pressure needed to move water upward and outward to your house.
Without a pump, water would stay in the ground. Gravity alone cannot lift it up a well shaft and into your plumbing system. The pump creates pressure that forces water up and out, and that same pressure keeps water flowing when you turn on a faucet or shower.
Key Takeaways
- A well pump pulls water from below ground and pressurizes it so it flows through your home's pipes.
- Submersible pumps sit underwater inside the well; jet pumps sit above ground and pull water up through a pipe.
- A pressure tank stores pressurized water so the pump does not run every time you use water.
- Most well pumps run on electricity and are controlled by a pressure switch that turns them on and off automatically.
- Sediment, low water levels, and electrical problems are the most common reasons well pumps fail or stop working.
The two main types: submersible and jet pumps
Submersible pumps are sealed units lowered into the well on a cable. The motor and pump are one piece, completely submerged below the water table. Water surrounds the motor and cools it as it runs. Submersible pumps are common in deeper wells (usually 25 feet or more) because they can push water up long distances without losing pressure. They are quieter than jet pumps and more efficient, but replacing one means pulling the entire unit out of the well—a job that usually requires a professional.
Jet pumps sit above ground, typically in a basement, garage, or pump house. A pipe runs down into the well, and the pump pulls water up through that pipe using suction and pressure. Jet pumps work well in shallower wells (usually under 25 feet) and are easier to repair or replace because they are accessible. The trade-off is that they are noisier and less efficient than submersible pumps, and they cannot lift water from very deep wells.
Your well depth and your home's water demand determine which type makes sense. A well driller or pump installer can tell you what your well requires based on how far down the water table sits in your area.
How pressure and the pressure tank keep water flowing
When you turn on a faucet, you expect water to come out when ready. That when ready flow happens because of a pressure tank—a metal or plastic tank that stores water under pressure. The pump fills this tank until pressure inside reaches a set level (usually 60 pounds per square inch, or PSI), then a pressure switch shuts the pump off. As you use water, pressure in the tank drops. When it falls below a lower threshold (usually around 40 PSI), the switch turns the pump back on.
Without a pressure tank, the pump would have to start and stop dozens of times a day—every time you turned on a faucet. That constant cycling would wear out the pump quickly and waste electricity. The tank acts as a buffer, letting the pump run in longer, less frequent cycles and keeping steady pressure in your pipes.
The pressure tank also contains a rubber bladder or diaphragm that separates air from water. As the tank fills, water compresses the air, which then pushes back when you draw water out. This air-water balance is what maintains pressure. If the bladder fails or the air charge leaks out, the tank stops working properly and the pump cycles too often.
The pressure switch and electrical control
A pressure switch is a straightforward mechanical device that monitors the pressure in your tank. It has two settings: a lower threshold (cut-in pressure) and an upper threshold (cut-out pressure). When pressure drops to the cut-in point, the switch closes an electrical circuit and the pump turns on. When pressure rises to the cut-out point, the switch opens the circuit and the pump stops.
Most residential well pumps run on 240-volt household electricity. A check valve sits between the pump and the pressure tank to prevent water from flowing backward into the well when the pump shuts off. Without it, pressure would drop when ready and the pump would restart constantly.
Some systems include a pressure relief valve that opens if pressure gets too high, protecting the tank and pipes from damage. If you hear the pump running but no water is coming out, or if water spurts and stops, the check valve or relief valve may be stuck or leaking.
What happens when sediment or sand gets into the pump
Well water often contains fine sediment, sand, or silt—especially in newer wells or after heavy rain. When sediment reaches the pump, it acts like sandpaper on the internal parts. Submersible pumps are more vulnerable because water flows directly through the motor housing. Sand can scratch the pump's impeller (the spinning part that moves water) and seals, causing the pump to lose pressure or stop working altogether.
A sediment filter or screen at the pump intake can catch larger particles before they enter the pump. Some wells have a sediment trap—a small basin below the pump intake that collects heavy particles. If your well is producing cloudy or sandy water, the pump intake may need cleaning or the well may need to be developed (flushed) by a professional to clear out loose sediment.
If sediment damage occurs, the pump usually cannot be repaired in the field. It has to be pulled out and either rebuilt or replaced. This is one reason regular maintenance and water testing matter: catching sediment problems early is cheaper than replacing a pump.
Low water level and dry well shutoffs
If your well water table drops below the pump intake, the pump will pull air instead of water. Running dry damages the pump because there is no water to cool the motor (in submersible pumps) or to lubricate the internal parts. Most modern pumps have a dry-run protection switch that senses when water is no longer flowing and shuts the pump off automatically to prevent damage.
Seasonal changes, drought, or heavy household use can lower the water table temporarily. If your well runs dry, the pump will not restart until water level rises again. A professional can test your well's recovery rate—how fast water refills after use—to determine if the well is undersized for your household or if the problem is temporary.
If dry-run shutoffs happen frequently, you may need a larger pressure tank to store more water between pump cycles, or the well itself may need to be deepened. A well contractor can assess whether the issue is the well or the pump system.
Common signs a well pump is failing
A well pump usually gives warning signs before it stops working completely. Reduced water pressure at your taps suggests the pump is losing efficiency or the pressure tank is waterlogged. Spurting or sputtering water indicates air in the lines, often from a failing check valve or a leak on the intake side. The pump running constantly means the pressure switch is not shutting it off—usually because pressure is not building, which points to a leak, a waterlogged tank, or a worn pump.
Cloudy or discolored water can mean sediment is reaching your taps, suggesting the pump intake screen is clogged or the pump is breaking down internally. Electrical tripping—the breaker shutting off power to the pump—often means the motor is drawing too much current, usually from age or internal damage.
If you notice any of these signs, have the system inspected by a well pump professional. Many problems are easier and cheaper to fix early. A technician can test pressure, check the switch settings, inspect the tank, and listen to the pump to diagnose what is happening.
When to call a professional
Well pump work involves electricity, pressurized water, and equipment that sits underground. Troubleshooting and repairs should be handled by a licensed well pump technician or plumber with well experience. They have the tools to pull a submersible pump from a deep well, test pressure and electrical circuits, and diagnose whether the problem is the pump, the tank, the switch, or the well itself.
You can do straightforward things yourself: check that the breaker has not tripped, listen for the pump running, and look for visible leaks around the pressure tank. But if the pump is not running, water pressure is low, or you hear unusual noises, call a professional. Attempting to repair a pressurized system or work inside a well without proper equipment can be dangerous and may damage the system further.
Frequently Asked Questions
How often should a well pump be replaced?
A well pump typically lasts 8 to 15 years depending on water quality, how often it runs, and whether it has been maintained. Submersible pumps often last longer than jet pumps. If your pump is over 10 years old and starting to show signs of wear, ask a technician whether replacement or repair makes sense.
Why does my well pump keep running?
The pump runs continuously when the pressure switch is not shutting it off. Common causes are a leak in the pressure tank, a waterlogged tank, a failed check valve, or a leak on the intake line. A technician can test the pressure and switch to find the source.
Can I use a well pump with a city water backup?
Yes. A check valve and a one-way switch can let you use well water normally but automatically switch to city water if the well fails. This requires a licensed plumber to install safely and to meet local codes.
What does it mean if my water is cloudy or has a rotten egg smell?
Cloudiness usually means sediment is in the water, often from the pump intake or the well itself. A rotten egg smell indicates hydrogen sulfide gas, which is a water quality issue, not a pump problem. Both require water testing and may need a filter or treatment system, not pump repair.
How deep can a jet pump pull water from?
A jet pump can reliably pull water from about 25 feet or less. Beyond that, suction becomes difficult and pressure drops. For deeper wells, a submersible pump is the standard choice.