When your well pump won’t start, you lose more than water—you lose momentum in your day. Before calling a pro, you can safely walk through a systematic well pump troubleshooting process to pinpoint where the failure might be. With a few simple tools—a multimeter, a flashlight, and basic hand tools—you can perform a DIY well inspection, run a pressure switch test, and attempt a well pump reset. This guide covers the practical steps to diagnose a no-start scenario, whether you have a jet pump or a submersible pump with a pump control box.
Safety First
- Turn off power at the breaker feeding the well system before opening any electrical covers. Verify power is off with a non-contact voltage tester or multimeter. Avoid working inside the well casing. Submersible pump testing at the wellhead should be done cautiously; if you’re unsure, call a licensed well contractor. If wires are burnt, insulation is brittle, or you smell ozone, stop and contact a professional.
Step 1: Confirm the Symptom and Check Basics
- Verify there is no water at fixtures and that the well pressure gauge at the pressure tank reads below the cut-in pressure (commonly 30–40 PSI). If pressure is above cut-in, the pump may be off because the system is already at pressure—open a faucet to lower pressure and see if the pump engages. Ensure all valves between the well and the house are open and any sediment or cartridge filters are not clogged. Look for obvious leaks around the pressure tank, switch, and piping.
Step 2: Verify Power and Breakers
- Check the main service panel for a breaker tripped on the well circuit. If tripped, reset it once. If it trips again immediately, you likely have a short, motor fault, or seized pump—stop and call a pro. Some systems have a local disconnect near the pressure tank or pump control box; ensure it’s on. If the system uses a GFCI or fused switch, inspect and reset/replace as needed.
Step 3: Inspect the Pressure Switch
Most residential well systems use a mechanical pressure switch to control the pump.
- With power off, remove the cover. Inspect contacts for pitting, corrosion, or insects. Gently tap the switch base; if contacts chatter or fail to close when pressure is low (as shown by the well pressure gauge), the diaphragm or spring may be faulty. Pressure switch test for function: Restore power and open a faucet to drop pressure below cut-in. Do the contacts snap closed? If not, the switch may have failed. Replace the switch if mechanically unresponsive. If contacts do close but the pump doesn’t start, continue to electrical tests.
Note: Never stick tools into a live switch. Observe from a safe distance, or turn off power and use a multimeter.
Step 4: Measure Voltage with a Multimeter
Determine if power is reaching the switch and leaving it toward the pump.
- With the breaker on and using appropriate PPE, set your multimeter to measure AC voltage. Measure line voltage at the switch’s line terminals (from L1 to L2). For most systems you should see ~240V (or ~120V in some installations). Measure load voltage at the switch’s load terminals (to the pump/control box) when the contacts are closed. You should see the same voltage as the line side. No voltage on line side: issue upstream (breaker, wiring). Voltage on line but not on load with contacts closed: bad switch or damaged contacts. Voltage present on load: proceed downstream.
If you’re uncomfortable testing live voltage, stop and call a professional.
Step 5: Identify Your Pump Type and Components
- Jet pump: Usually above ground near the pressure tank. You can listen for hums or buzzes. Submersible pump: Located in the well casing. System often includes a pump control box (for 3‑wire pumps) mounted near the pressure tank.
If you have a control box, it may contain a start capacitor, run capacitor, and relay. These components commonly cause a no-start.
Step 6: Check the Pump Control Box (for 3‑wire submersibles)
- Turn off power. Open the control box and look for burned components or bulging capacitors. Label and photograph wire positions. Electrical continuity tests: With power off and caps discharged, use your multimeter in ohms to check continuity of the start and run windings through the cable to the pump (typically labeled R, Y, B at the box). Typical reading patterns: Each pair will have a specific resistance range; an open circuit indicates a broken conductor or failed winding. Consult the pump’s manual for expected values. If capacitors are visibly bulged or you measure out-of-spec capacitance (if your multimeter supports it), replace the capacitor(s) and the relay as a set if age/condition is unknown.
Tip: Replacing a pump control box is relatively simple and often resolves no-start issues in older systems.
Step 7: Try a Well Pump Reset
Some systems have:
- A reset button on the pressure switch (low-pressure cut-off style). A thermal overload reset on the motor (jet pump) or within the submersible motor. A reset or manual lever on the pump control box.
Procedure:
- Turn off power for 10–15 minutes to allow thermal overloads to cool. If you have a low-pressure cut-off switch, hold the lever or reset per manufacturer instructions while a faucet is open to allow the pump to prime and pressure to rise past cut-in. Restore power and observe the pressure gauge: does pressure rise smoothly? If it starts and immediately trips again, suspect a seized pump, shorted cable, or a failing capacitor/relay.
Step 8: Evaluate Pressure Tank and Switch Settings
- Check the tank’s air precharge (power off, drain water until gauge reads 0). Measure at the Schrader valve with a tire gauge; it should be 2 PSI below the switch cut-in (e.g., 38 PSI for a 40/60 switch). Incorrect precharge can cause rapid cycling or failure to close the pressure switch reliably. If the tank is waterlogged (no air cushion), the pump may short-cycle and fail to start consistently.
Step 9: Submersible Pump Testing at the Wellhead
- Inspect the well cap and the splice where the drop cable connects to the house wiring. Look for corrosion, loose wirenuts, or water intrusion. With power off, ohm out the motor leads back to the control box to confirm electrical continuity. Compare to manufacturer specs. Perform an insulation resistance test (megger) to check for shorts to ground, if available. Low insulation resistance suggests a compromised cable or motor—call a pro.
Warning: Do not pull a pump without proper equipment. A stuck or heavy drop pipe can be dangerous.
Step 10: Jet Pump Checks (if applicable)
- Verify pump is primed. A dry pump won’t develop suction and may overheat. Listen for humming without rotation—this can indicate a stuck impeller or bad start capacitor. Check for clogged foot valve or air leaks on the suction line; air leaks prevent priming.
Decision Points
- Breaker tripped repeatedly: likely short or motor fault—professional service recommended. Good voltage to pump/control box but no start: suspect capacitor/relay, failed motor, or broken drop cable. Pressure switch defective: replace and retest. Water at low yield or dry well: pump may be in thermal overload due to running dry; allow recovery and consider a pump protection device.
Tools You’ll Need
- Multimeter (AC voltage, resistance; capacitance helpful) Non-contact voltage tester Screwdrivers and nut drivers Tire gauge and air pump for tank precharge Flashlight Camera/phone for wiring documentation
When to Call a Professional
- You’re not comfortable working around live electrical circuits. Repeated breaker trips, burning smells, or visible arcing. Insulation resistance is low or windings test open. Submersible pump testing indicates a motor or cable fault. You need to pull the pump or replace buried wiring.
By following this structured approach—starting with the well pressure gauge, eliminating a breaker tripped condition, performing a pressure switch test, and verifying voltage and electrical continuity with a multimeter—you’ll isolate most no-start issues quickly. A careful DIY well inspection often reveals a straightforward fix like a failed pressure switch, a bad capacitor in the pump control box, or the need for a simple well pump reset. More complex faults, especially below ground, are best left to pros.
FAQs
Q: My pressure gauge reads 0 PSI, and the pump won’t start. What should I try first? A: Check for a breaker tripped and reset once. Inspect the pressure switch; if it has a low-pressure cut-off, hold the reset/lever while opening a faucet to re-establish pressure. Verify voltage with a multimeter at the switch.
Q: How do I know if the pressure switch is bad? A: If system pressure is below cut-in but the contacts don’t close, or there’s voltage on the line side but none on the load side when contacts appear closed, the switch is likely faulty. Replace it and recheck operation.
Q: My control box capacitor looks fine; could it still be bad? A: Yes. Capacitors can fail without visible bulging. Test with a meter that reads capacitance or replace the start/run capacitor and relay as a set if symptoms point to no-start.
Q: The breaker trips as soon as the pump calls for water. What’s the cause? A: Common causes include a shorted motor, damaged drop cable, seized pump, or failed capacitor/relay causing excessive inrush. Stop resetting repeatedly and call a professional.
Q: Can I test a submersible pump without pulling it? Plumber A: You can perform resistance and insulation tests from the control box or wellhead to assess windings and cable integrity. True mechanical issues or impeller problems generally require pulling the pump.
