Well Pump Not Working: Common Causes and Troubleshooting Steps

A non-functioning well pump represents one of the most disruptive residential water system failures, cutting off potable water supply to the entire property. This page covers the primary mechanical, electrical, and pressure-related failure modes responsible for well pump outages, the diagnostic framework used by licensed well contractors, and the decision boundaries that separate owner-verifiable conditions from those requiring licensed intervention. The scope applies to private residential and light commercial groundwater systems across the United States, where the Environmental Protection Agency (EPA) estimates approximately 13 million households rely on private wells.

Definition and scope

A well pump failure is defined as any condition in which the pump assembly — including its motor, pressure switch, control box, or associated piping — ceases to deliver water at the designed flow rate and pressure to the structure it serves. The failure may be total (zero flow) or partial (reduced pressure, intermittent cycling, or contaminated output).

Well pump systems fall into two primary classifications that govern diagnosis and repair access:

Submersible pumps — installed below the water table inside the well casing, typically at depths of 25 to 400+ feet. The motor and pump are a single sealed unit. Physical access requires pulling the drop pipe from the well, a process governed by state well construction codes.
Jet pumps — installed above ground at or near the wellhead, drawing water through suction. Shallow-well jet pumps function at depths up to approximately 25 feet; deep-well jet pumps extend to roughly 90 feet using a two-pipe ejector assembly.

The distinction matters operationally: jet pump components are generally accessible without specialized well-pulling equipment, while submersible pump diagnosis and replacement require licensed well contractors in most jurisdictions. State well codes — administered through agencies such as individual state departments of environmental quality or health — define minimum standards for pump installation, casing integrity, and wellhead protection. A directory of well contractors operating under these standards is available through the Well Pump Repair Listings index.

How it works

Both pump types operate on the same hydraulic principle: mechanical energy moves water from the aquifer into a pressure tank, which stores pressurized water for household delivery. The pressure switch monitors tank pressure and cycles the pump on and off between two set points — commonly 30 PSI (cut-in) and 50 PSI (cut-off), though 40/60 PSI settings are standard in higher-demand systems.

The submersible system's operational sequence:

Pressure in the tank drops below the cut-in threshold.
The pressure switch closes, sending 240-volt power (in most residential installations) to the control box.
The control box regulates starting capacitance and sends power down the drop cable to the submersible motor.
The impeller stack pressurizes water upward through the drop pipe and into the pressure tank.
Pressure reaches the cut-off point; the switch opens and the motor stops.

Jet pump systems replace steps 2–4 with an above-ground motor driving an impeller or ejector-venturi assembly. The absence of a sealed downhole motor means electrical faults are more directly accessible but the system is more vulnerable to loss of prime — a condition where air infiltrates the suction line, breaking the water column.

Common scenarios

Failure presentations in well pump systems cluster around five diagnostic categories:

No power to the pump — Tripped circuit breaker, blown fuse at the disconnect box, failed pressure switch contacts, or a burned wire at the control box. This is the first category to verify before any mechanical diagnosis.
Pump runs but delivers no water — Indicates a dry well (aquifer drawdown), a broken drop pipe, a failed foot valve or check valve, or a burned impeller. In jet pump systems, loss of prime produces identical symptoms.
Pump short-cycles (rapid on/off) — Waterlogged pressure tank (failed or undercharged bladder/diaphragm) is the leading cause. A properly functioning tank maintains an air charge; the Water Systems Council recommends pre-charge pressure set to 2 PSI below the cut-in setting.
Low pressure or reduced flow — Partially blocked screen, worn impellers, partially closed gate valve, or a pressure switch set point that has drifted. Mineral scaling in hard-water regions (particularly calcium carbonate at concentrations above 150 mg/L) accelerates impeller wear.
Pump hums but does not start — A seized motor, failed start capacitor (submersible control box or jet pump capacitor), or a locked impeller from scale or debris. Voltage at the motor terminals without rotation is a fire and motor-burnout risk under NFPA 70 (National Electrical Code) Article 430 guidelines for motor overcurrent protection.

For professional context on contractor qualifications serving these failure types, the Well Pump Repair Directory Purpose and Scope page describes credentialing categories and regional licensing structures.

Decision boundaries

The boundary between owner-verifiable checks and licensed-contractor work is defined primarily by access depth, voltage class, and state regulatory requirements.

Owner-verifiable without licensing:
- Checking and resetting the circuit breaker at the main panel
- Inspecting the wellhead disconnect box for a tripped breaker or visible burned wire
- Verifying pressure tank pre-charge with a tire gauge at the Schrader valve (pump must be off and system depressurized)
- Confirming the pressure switch is not visibly corroded or damaged

Requires licensed well contractor or electrician:
- Any repair or replacement of a submersible pump, motor, or drop pipe — which constitutes well construction activity regulated under state well codes
- Replacement of the control box or pressure switch wiring in 240-volt systems
- Camera inspection or water level measurement in the well casing
- Any work crossing the well seal or casing

Permit requirements for pump replacement vary by state. In states including California, Texas, and Florida, pump replacement within an existing casing may require a well construction permit or licensed contractor notification to the state agency of record. The How to Use This Well Pump Repair Resource page describes how to locate contractors holding applicable state licenses.

Electrical work on well pump systems falls under NFPA 70 jurisdiction, and pump installations must comply with applicable sections of the International Plumbing Code (IPC) as adopted at the state level. Groundwater protection requirements — including wellhead setback distances and casing standards — are governed by EPA Underground Injection Control regulations and individual state primacy programs.

References

📜 1 regulatory citation referenced · ✅ Citations verified Feb 25, 2026 · View update log