System guide
The Private Well Pump Guide: How Your Well System Works
More than 43 million Americans get their water from a private well. The system behind the faucet is simpler than it looks — and knowing it is the best protection against an expensive misdiagnosis.
On this page
A private well system has five working parts: the pump (in the well or beside it), a check valve that holds water in the pipe, a pressure tank that stores water on an air cushion, a pressure switch that starts and stops the pump, and the electrical supply (breaker, and on three-wire pumps a control box). Most problems show up as a symptom at the faucet or on the pressure gauge long before the pump itself fails.
Your well, your responsibility
The U.S. Geological Survey estimates that more than 43 million people — about 15% of the U.S. population — rely on domestic wells.[1] The EPA does not regulate private wells; the owner is responsible for the water and the equipment.[2] The CDC suggests checking your well every spring for mechanical problems and testing the water at least once a year.[3]
How the system works
A typical submersible-pump system. Jet-pump systems put the pump above ground instead (see the pump-type comparison).
- Pump and motor — sits below the water level and pushes water up.
- Check valve — keeps water from draining back down the well when the pump stops. Often built into the pump; more may be installed higher up.
- Pitless adapter — where the line leaves the casing, below the frost line.
- Pressure tank — an air cushion stores water under pressure so the pump doesn't start for every glass of water.
- Pressure switch and gauge — the switch turns the pump on at the cut-in pressure and off at the cut-out pressure.
- House supply — filters, softeners and treatment equipment usually sit on this line.
- Electrical supply — a dedicated breaker feeds the pressure switch, which switches power down the well. Three-wire pumps also have a control box on this circuit.
When you open a faucet, water comes first from the pressure tank. As the tank empties, pressure falls to the switch's cut-in setting, the switch closes, and the pump runs until pressure reaches cut-out. The check valve keeps the water column from falling back down the well when the pump stops, which also protects the pump from spinning backward — Franklin Electric explains that missing or leaking check valves cause backspin, upthrust and water hammer, any of which can lead to early pump or motor failure.[4]
Pump types
Jet pumps pull (suction) or recirculate water through an ejector; submersibles push. Depth figures are manufacturer guidance for shallow-well jets (Pentair: a deep-well package may be needed beyond 25 ft to water).
| Type | Where it sits | Best suited to | Installed cost (HomeGuide) |
|---|---|---|---|
| Shallow-well jet | Above ground; pulls water up a suction pipe | Water within about 25 ft of the pump (Pentair's shallow-well limit)[5] | $400–$1,000 |
| Deep-well (convertible) jet | Above ground, with an ejector down the well | Moderately deep water where a submersible isn't practical | $500–$1,400 |
| Submersible | In the well, below the water; pushes water up | Most drilled wells, especially deeper ones | $1,000–$2,500 |
| Constant-pressure (variable-speed) | Usually a submersible with a variable-speed drive | Steady pressure, smaller tank | $2,000–$5,000 |
Installed costs are HomeGuide's published ranges.[6] Full comparison: submersible vs. jet pumps; upgrade option: constant-pressure systems.
The specs that matter
Reading a pump's label and paperwork
- Flow (GPM)
- Gallons per minute the pump delivers — but only at a given head. The pump curve shows how flow falls as head rises.
- Head (feet)
- The total height and resistance the pump works against. Pressure counts too: manufacturers convert with 1 psi = 2.31 feet of head.[7]
- Horsepower (HP)
- Motor size. More HP isn't "better" — it has to match the head and flow you need and what the well can supply.
- Voltage
- Typically 115 V or 230 V single-phase for homes. Franklin requires the supply to be within 10% of the motor's rating.[4]
- Two-wire or three-wire
- Whether the starting parts are inside the motor or in an above-ground control box.[4] See controls.
- Diameter
- Residential submersibles are commonly 4-inch units (Franklin lists its 4-inch motors as the standard water-well size), so they need a casing wide enough to take them.[4]
Total head, simply
A pump has to do three things: lift water from the pumping level to the surface, push it through the pipes (friction), and deliver it at pressure. Amtrol's sizing handbook walks through an example: water 240 feet down, plus 30 psi at the tank (30 × 2.31 ≈ 70 feet of head), means the pump must produce about 310 feet of head at the cut-in point, and more at cut-out.[7] That's why raising the switch setting can push an older pump past its limit.
How long well pumps last
No pump maker publishes a guaranteed service life, and it varies with water quality, sand, how often the pump starts and whether it has ever run dry. Cost publishers report typical ranges — HomeGuide says 10 to 15 years in its replacement guide and 8 to 15 years in its repair guide.[6][8] What shortens life is better documented than how long it lasts:
- Frequent starts. Franklin ties the number of starts per day directly to system life and lists maximum starts for each motor size.[4] Keep the pressure tank healthy.
- Running without enough water. Submersible motors rely on water flowing past them for cooling.[4]
- Missing or failed check valves (backspin, upthrust, water hammer).[4]
- Surges and lightning — Franklin's installation checklist calls for a dedicated surge arrestor.[4]
- Sand and scale wearing impellers and clogging intakes.
Guides in this section
- ComparisonSubmersible vs. jet pumpsDepth limits, noise, priming, service access and installed cost.
- Upgrade guideConstant-pressure well systemsSteady pressure from a variable-speed pump — costs, rules and trade-offs.
- Troubleshooting hubWell pump troubleshootingMatch your symptom to its likely causes and the safe first checks.
- Cost guideWell pump replacement costPublished ranges by pump type, add-on parts and a quote checklist.
Warning signs worth acting on
- The pump starts every time you open a faucet → short cycling.
- The pump runs a long time or doesn't shut off → keeps running.
- Pressure is weaker than it used to be → low water pressure.
- Sputtering faucets, cloudy or sandy water → a pump or well problem that deserves a contractor's visit.
- The breaker trips → breaker keeps tripping.
Sources
- U.S. Geological Survey. Domestic (Private) Supply Wells. Accessed Sept. 28, 2026.
- U.S. Environmental Protection Agency. Private Drinking Water Wells. Accessed Sept. 28, 2026.
- Centers for Disease Control and Prevention. Guidelines for Testing Well Water. Accessed Sept. 28, 2026.
- Franklin Electric. Submersible Motors: Application, Installation & Maintenance (AIM) Manual, 60 Hz. Accessed Sept. 28, 2026.
- Pentair. Pro Shallow Well Jet Pumps — Installation & Operation Manual (P15001, 2023). Accessed Sept. 28, 2026.
- HomeGuide. How Much Does a Well Pump Cost To Replace or Install? (article dated Aug. 7, 2025). Accessed Sept. 28, 2026.
- Amtrol. Sizing the Well-X-Trol (commercial sizing handbook). Accessed Sept. 28, 2026.
- HomeGuide. How Much Does Well Pump Repair Cost? (article dated Aug. 6, 2025). Accessed Sept. 28, 2026.
We cite manufacturer documentation and public agencies first. Read how we choose and check sources.