Well Pump Not Working: Causes and Solutions

A non-functioning well pump is one of the most disruptive failures a residential or agricultural water system can experience, cutting off the primary water supply to a structure that depends entirely on groundwater access. Failures range from complete loss of pressure to intermittent cycling, and the underlying causes span electrical faults, mechanical wear, pressure system failures, and well-related conditions. This page describes the service landscape for well pump diagnosis and repair, the classification of failure types, and the professional and regulatory framework that governs well pump work in the United States. For a broader overview of how this sector is organized, see the Well Pump Directory Purpose and Scope.

Definition and scope

A well pump failure is any condition in which a pump-based water supply system fails to deliver water at design pressure and flow rate to connected plumbing. The scope of failure encompasses the pump itself, the pressure tank, the control circuitry, the drop pipe, the well casing, and the water table conditions of the aquifer being drawn from.

Well pumps fall into two primary classifications with distinct failure profiles:

• Submersible pumps — installed below the waterline inside the well casing, typically at depths between 100 and 400 feet for residential systems. Submersible pumps require extraction from the well for physical inspection and service.
• Jet pumps — installed above ground, either as shallow-well (suction lift up to approximately 25 feet) or deep-well configurations. Jet pumps are accessible for inspection without well extraction but depend on priming and foot-valve integrity.

The distinction between these two types determines the diagnostic pathway, service access method, and labor scope involved in any repair or replacement.

Well pump systems operate under regulatory oversight through state-level well construction and pump installation codes. The U.S. Environmental Protection Agency (EPA) provides baseline guidance on private well maintenance and water quality for the approximately 13 million households served by private wells in the United States (EPA, Private Drinking Water Wells). State agencies — such as departments of environmental quality or natural resources — license well drillers and pump installers under statutes that vary by jurisdiction.

How it works

A submersible pump uses a sealed motor coupled directly to a multi-stage centrifugal impeller assembly. When the pressure tank drops below a set cut-in pressure (commonly 30 PSI in a 30/50 PSI switch configuration), the pressure switch energizes the pump circuit. The motor spins the impellers, lifting water through the drop pipe to the pressure tank, where it is stored under compressed air charge until the cut-out pressure (commonly 50 PSI) is reached and the switch opens the circuit.

A jet pump operates on the Venturi principle: a pressurized jet of water passes through a narrow nozzle, creating a low-pressure zone that draws water from the well. Shallow-well jet pumps locate the ejector inside the pump housing; deep-well jet pumps position the ejector assembly at the bottom of the drop pipe.

The pressure tank's function is to buffer on/off cycling. A waterlogged pressure tank — one that has lost its air charge — causes the pump to short-cycle, switching on and off in intervals of under 30 seconds. Repeated short-cycling accelerates motor winding failure and bearing wear.

Control components include the pressure switch, the capacitor (start and run capacitors in single-phase motors), the pressure gauge, and the check valve. Each represents a discrete failure point that can be isolated without pulling the pump.

Common scenarios

Well pump failures cluster into five identifiable categories:

1. No water at all — Complete loss of output. Possible causes include tripped circuit breaker, failed pressure switch, burned motor windings, dry well, or broken drop pipe.
2. Low water pressure — Reduced but present flow. Associated with worn impellers, partially clogged intake screen, or a pressure switch set point that has drifted.
3. Short cycling — Pump activates and deactivates at intervals shorter than 1 minute. Strongly indicates a waterlogged pressure tank or a failed bladder in a bladder-type tank.
4. Pump runs continuously without reaching cut-out pressure — Indicates a leak in the distribution system, a failed check valve allowing backflow, significant impeller wear, or a drop in static water level below the pump intake.
5. Discolored or sediment-laden water — May indicate well screen failure, casing infiltration, or pump wear introducing particulate material into the water column. This scenario has water quality implications that intersect with EPA and state environmental guidelines.

Comparing submersible versus jet pump diagnostics: jet pump failures are more frequently traceable to above-ground components (priming loss, foot valve failure, motor capacitors), while submersible failures more often require pump extraction and motor testing using a megohmmeter to measure winding insulation resistance — a value below 1 megohm typically indicates a damaged motor winding (per NEMA MG 1 motor standards).

Decision boundaries

The decision to repair versus replace a well pump involves technical, regulatory, and economic thresholds:

• Electrical testing first — Before any mechanical work, licensed electricians or pump contractors verify supply voltage at the pressure switch and pump terminals. Voltage drop exceeding 10% below nameplate rating degrades motor performance and must be resolved at the service panel level before pump work proceeds.
• Permitting requirements — Well pump replacement in a large number of U.S. states requires a permit from the state agency overseeing well construction. Pulling a submersible pump for replacement without the required permit can trigger inspection and water quality testing mandates. Contractors operating without a state pump installer license face civil penalties under state well codes.
• Water quality testing triggers — The EPA recommends annual testing for coliform bacteria and nitrates in private wells. Any intrusive pump work that disturbs the casing seal creates a mandatory disinfection step under most state well codes before the well returns to service.
• Age thresholds — Submersible pump motors have a manufacturer-rated service life generally between 8 and 15 years depending on duty cycle and water chemistry. A motor approaching or beyond 15 years in service with a winding failure is typically evaluated for full replacement rather than rewind repair.

Professionals in this sector — well drillers, pump installers, and plumbing contractors — operate under distinct licensing categories in most states. The Well Pump Listings directory covers licensed service providers by state and service type. For an overview of how this reference resource is structured, see How to Use This Well Pump Resource.

References

• U.S. Environmental Protection Agency — Private Drinking Water Wells
• NEMA MG 1: Motors and Generators (National Electrical Manufacturers Association)
• National Ground Water Association (NGWA) — Well Owner Resources
• EPA Groundwater and Drinking Water — Well Maintenance Guidance
• NFPA 70: National Electrical Code (NEC) — relevant to pump wiring and overcurrent protection (National Fire Protection Association)