How To Tell If Well Is Dry Or Pump Bad: Definitive Diagnostic Guide

Diagnosing whether a water well has run dry or if the pump has failed involves checking electrical power supplies, monitoring pressure tank behavior, and evaluating the well's specific recovery rate. By systematically isolating the pressure switch, control box, and flow rate, property owners can accurately distinguish between a depleted aquifer and mechanical pump failure.

Pre-Operation & Safety Checklist

Troubleshooting an electrical water pumping system requires a structured approach to prevent equipment damage and personal injury. Before opening electrical panels or checking plumbing lines, gather the necessary diagnostic tools and understand the safety standards associated with high-voltage well systems.

• Essential Gear and Tools: Digital Multimeter capable of measuring AC/DC voltage and continuity, Clamp-on ammeter for measuring running amps, insulated screwdrivers, slip-joint pliers, and a clean bucket for flow testing.
• Prerequisite Knowledge & Standards: Familiarity with National Electrical Code (NEC) safety protocols regarding 230V circuits, understanding of standard well pump pressure cycles (typically 30/50 or 40/60 PSI), and awareness of local water table depths.
• Estimated Budget and Duration: Basic diagnostic testing takes between 45 to 90 minutes. Professional service calls for pump pulling or down-hole camera inspections range from 300 to 1,500 dollars depending on well depth.

Step-by-Step Well vs. Pump Diagnostic Procedure

Step 1: Inspect the Electrical Supply and Pressure Switch

1. Locate the pressure switch attached to the supply line near the pressure tank. Remove the plastic cover to expose the electrical contacts.
2. Check the contacts for signs of burning, pitting, or insect nests that could prevent electrical closure.
3. Observe the switch points while draining the pressure tank. If the contacts close when pressure drops below the cut-in threshold (e.g., 30 PSI) but the pump does not hum or activate, power is failing to reach the pump.
4. Measure the incoming voltage at the line side and load side of the pressure switch using your digital multimeter set to AC voltage.

Warning: Exercise extreme caution when testing live electrical components. 230-volt well circuits can cause severe shock or fatality. If you are uncomfortable working with high voltage, shut off the breaker and call a licensed electrician.

Step 2: Test the Control Box and Capacitors

1. For 3-wire submersible pumps, locate the external control box mounted on a nearby wall. Unscrew the cover to inspect the internal components.
2. Look for physical signs of electrical failure, such as a bulging or leaking start capacitor, charred wiring, or a strong burnt-plastic odor.
3. Use a multimeter to test the ohms resistance of the start and run capacitors according to the manufacturer specifications printed on the label.
4. Press the red overload reset button on the control box if it has tripped. If it trips immediately upon reset, the motor windings may be shorted or the pump is locked up due to sand infiltration.

Step 3: Evaluate the Pressure Tank and Water Delivery

1. Turn off the power to the well pump at the main breaker panel.
2. Drain all water from the pressure tank by opening a nearby hose bib or faucet until the pressure gauge reads zero.
3. Check the air pre-charge pressure at the Schrader valve on top of the pressure tank using a standard tire pressure gauge.
4. The tank's air pressure should measure exactly 2 PSI below the pump cut-in pressure (e.g., 28 PSI for a 30/50 switch). Water escaping from the Schrader valve indicates a ruptured internal bladder, which mimics pressure delivery issues.

Step 4: Perform the Bucket Test and Check Recovery Rate

1. Turn the power back on and allow the pump to run until it shuts off automatically at the cut-out pressure.
2. Open a raw water spigot before the filtration system wide open and catch the water in a measured 5-gallon bucket while timing the fill rate with a stopwatch.
3. Calculate the Gallons Per Minute (GPM) output. Compare this flow rate against the original well drilling report specifications.
4. Turn off the faucet and wait two hours. Turn the pump back on and observe if it pumps normally for a short period before sputtering and losing prime again. This intermittent recovery strongly points toward a low-yielding or dry well rather than a dead pump motor.

Diagnostic Comparison: Well Depletion vs. Pump Failure

Common Well and Pump Failure Scenarios

• Root Cause: Silt and sediment clogging the pump intake screen.
  
  
  • Actionable Fix: Pull the pump assembly, clean or replace the intake screen, and consider having a well professional surge or jet the well screen to clear fine particles from the aquifer formation.
• Root Cause: Shear pin or spline stripped on a submersible pump shaft.
  
  
  • Actionable Fix: The motor runs continuously, but the pump impellers do not spin. The pump unit must be pulled from the casing using a hoist truck to replace the drive assembly.
• Root Cause: Seasonal water table drop exceeding historical pump placement depth.
  
  
  • Actionable Fix: Lower the existing pump further down the casing if clearance permits, or drill the well deeper into the water-bearing bedrock formation.
• Root Cause: Foot valve failure on a shallow jet pump system.
  
  
  • Actionable Fix: The suction line loses its prime when idle. Replace the malfunctioning foot valve at the bottom of the drop pipe inside the well.

Frequently Asked Questions

Can a dry well damage a submersible pump?

Yes. Submersible pumps rely on surrounding water to cool the electric motor windings. Running a pump dry causes rapid overheating, which can melt the motor windings, ruin the internal bearings, and destroy the plastic impellers within minutes.

How do I know if my foot valve is leaking?

If your jet pump loses prime overnight or after a few hours of non-use, requiring you to manually re-prime the system before it pumps water, the foot valve is failing to hold water in the suction pipe. Replacing this underground check valve restores system pressure retention.

Is it possible for a well to go dry temporarily?

Yes. During extended droughts or periods of heavy agricultural and residential irrigation, local water tables can drop below the pump intake level. Once seasonal rainfall replenishes the aquifer, the well may resume normal production without requiring mechanical intervention.

What is the average lifespan of a well pump?

Standard submersible well pumps typically last between 10 to 15 years, depending on water quality, mineral content, and daily usage cycles. Hard water, high iron content, and abrasive sand particles significantly shorten pump operating lifespans.

Should I hire a professional or troubleshoot the well myself?

Homeowners can safely test electrical breakers, pressure switches, control boxes, and pressure tank air pre-charges. However, pulling a submersible pump from hundreds of feet underground requires specialized truck hoists, safety clamps, and heavy-duty lifting equipment best handled by licensed water well contractors.

Schedule an on-site evaluation with a licensed pump technician to perform down-hole camera inspections and flow testing for precise down-hole diagnostics.