When your well pump runs but the pressure won’t climb, it’s more than an inconvenience—it can indicate a mechanical, hydraulic, or electrical issue that needs prompt attention. This guide walks you through safe, systematic well pump troubleshooting steps to identify common causes, decide what you can handle with a DIY well inspection, and when to call a professional. Along the way, you’ll learn how to use a well pressure gauge, perform a basic pressure switch test, and apply a multimeter for electrical continuity checks.
Before you begin: safety first. Shut off the breaker to the well circuit when working on wiring or opening the pump control box, and depressurize the system if you plan to open plumbing fittings. If at any point you smell burning, see melted components, or suspect a short, stop and call a licensed well contractor.
Problem snapshot: pump runs continuously, but pressure stalls below the cut-off. Possible culprits include: lost prime (for jet pumps), clogged intake or filter, stuck or failed check valve, pressure switch miscalibration, pressure tank issues (air charge or bladder failure), suction or line leaks, worn impeller or broken coupling, or electrical problems in the pressure switch, control box, or motor windings.
Step-by-step diagnostic workflow
1) Verify the symptom with the well pressure gauge
- Observe the well pressure gauge at the pressure tank while the pump runs. Normal behavior: pressure rises steadily to the cut-off (often 50–60 psi) and stops. Fault condition: pressure holds low, fluctuates, or rises extremely slowly. Note the exact pressure where it “stalls.” This helps pinpoint restrictions versus leaks.
2) Check for obvious system restrictions
- Remove or bypass point-of-use filters and whole-house sediment filters temporarily. A clogged filter can trap pressure on the pump side and starve the house side. Inspect the sediment filter housing for collapse or blockage. Look for partially closed valves between the pump and pressure tank.
3) Inspect for leaks and air ingress
- Walk the line from the well to the tank. Listen for hissing, look for damp soil, and check fittings for drips. If you have a jet pump (above-ground), a suction-side leak will draw air, causing the pump to run without building pressure. Tighten fittings and re-do any suspect thread seals. If the pump cycles off but pressure drops quickly at rest, suspect a check valve or foot valve not sealing. For submersible pumps, the check valve is often integrated or placed near the tank; for jet systems, the foot valve is in the well.
4) Evaluate the pressure tank and switch interaction
- Turn off all water use and observe the gauge. If the pump runs but can’t achieve the cut-off, the problem may be upstream (pump/well) or with the pressure switch. Perform a basic pressure switch test: With power off at the breaker, remove the pressure switch cover. Inspect for pitted, burned, or stuck contacts. Lightly tap the switch body; if contacts chatter or fail to engage smoothly under pressure changes, replace the switch. Confirm the switch’s range (e.g., 30/50 or 40/60). If your pressure never reaches the cut-off and the switch is misadjusted too high, it may be commanding an unreachable target. Check tank air charge: Turn off power and drain water until the gauge reads zero. Use a tire gauge on the tank’s air valve. Pre-charge should be 2 psi below the cut-in (e.g., 28 psi for a 30/50 switch). If water comes out of the air valve, the bladder is ruptured; replace the tank. A waterlogged or undercharged tank won’t prevent pressure from building, but it causes rapid cycling that can mask other issues.
5) Confirm electrical supply and controls
- Breaker tripped? If so, reset and observe. A breaker that trips repeatedly indicates an electrical fault. At the pressure switch, with a multimeter and power on, carefully verify voltage on the line side (typically 240V or 120V, depending on your system) and that it passes through when the contacts close. For systems with a pump control box (common with three-wire submersible pumps), turn off power, open the box, and inspect for swollen capacitors, burned relays, or overheated components. Use a multimeter to check capacitor microfarads (per label) and relay continuity with power off. Electrical continuity tests: With power off and wires isolated, measure motor lead resistance to confirm none are shorted to ground and that winding resistances match manufacturer specs. Abnormal readings suggest motor or cable damage.
6) Consider pump-specific issues
- Jet pumps (above-ground): Lost prime: If you recently opened the suction line, the pump may be air-bound. Follow your pump’s priming instructions, ensuring the casing is fully flooded. Clogged jet or venturi: Mineral or sand can obstruct the jet, reducing output pressure. Disassemble and clean per manual. Worn impeller or broken coupling: A motor spinning freely with reduced water movement points to mechanical wear. Inspect and replace worn parts. Submersible pump testing: Listen for changes in pump sound at the pressure tank line; a “whine” without pressure often indicates worn impellers. If accessible, measure current draw while running. A significantly lower-than-nameplate current can indicate the pump is spinning but not moving water (e.g., sheared shaft or impeller damage). A higher current can indicate a partial blockage or mechanical drag. If you suspect a failed check valve or rising main leak below grade, you may need a contractor to pull the pump for inspection.
7) Rule out a low-yield well
- If pressure rises only when flow demand is minimal, the well may be underproducing. Check the well recovery: turn the pump off, let the well rest, then run water slowly while watching the well pressure gauge. If it drops and never recovers, your pump may be outrunning the aquifer, and protection controls (if installed) might be cycling the system. A flow test at the pressure tank with a timed bucket and stable gauge readings helps differentiate supply limits from mechanical faults.
8) Perform a controlled well pump reset
- After making corrections (tightening fittings, replacing a clogged filter, adjusting pre-charge), turn off all fixtures. Restore power at the breaker, ensuring the pressure switch is closed at cut-in. Monitor the gauge. Pressure should climb steadily to the cut-off and the pump should stop cleanly. If the pressure still won’t build, escalate to component replacement or professional evaluation.
Common fixes and when to escalate
- Replace a clogged whole-house filter or collapsed cartridge. Replace a failed pressure switch or burnt contacts. Re-prime a jet pump and seal suction fittings. Adjust the pressure tank pre-charge to match the pressure switch cut-in. Clean or replace a stuck check valve near the tank. If electrical tests in the pump control box or submersible pump testing indicate winding faults, short-to-ground, or sustained abnormal current, call a licensed well contractor. Pulling a pump, replacing drop pipe, or addressing downhole leaks is not a DIY well inspection.
Tools checklist
- Multimeter rated for your system voltage Pressure/tire gauge for tank pre-charge and the installed well pressure gauge for live monitoring Basic hand tools, thread sealant/tape Replacement pressure switch and filter cartridge (optional) Electrical PPE and lockout for safe work
Pro tips
- Label your pressure switch settings (e.g., 40/60) and record gauge readings during tests; it speeds future well pump troubleshooting. Don’t overtighten pressure switch springs; small adjustments go a long way. If in doubt, replace rather than tweak. If you find sand or rust in filters or fixtures, schedule a professional inspection—abrasives can rapidly wear impellers and jets.
Questions and Answers
Q1: How do I know if the pressure switch is bad versus misadjusted? A1: If contacts are burned/pitted or fail to close at cut-in pressure, it’s bad. If it closes but your cut-off is set unrealistically high (e.g., 70 psi on a small pump), lower the setting or install the correct 30/50 or 40/60 switch. A quick pressure switch test with the cover off will reveal contact action.
Q2: Can a pressure tank cause low pressure by itself? A2: A bad tank won’t usually prevent building pressure, but it causes rapid cycling and unstable readings. If the bladder is ruptured (water at the Schrader valve) or the pre-charge is off, fix it to protect the pump and get consistent performance.
Q3: What does a breaker tripped indicate in this scenario? A3: A nuisance trip suggests shorted wiring, a failing capacitor, locked rotor, or a ground fault. Restore power only after inspecting the pressure switch, pump control box, and motor leads with a multimeter and electrical continuity checks.
Q4: How often should I do a DIY well inspection? A4: At least annually: check the well pressure gauge behavior, replace filters, commercial pumps Union CT verify tank pre-charge, inspect the pressure switch, and test the control box if equipped. Record baseline readings to spot changes early.
Q5: When should I avoid DIY and call a pro? A5: If you suspect a downhole issue, need to pull a submersible, find melted wiring, fail continuity/insulation tests, or if pressure still won’t build after addressing filters, switch, pre-charge, and visible leaks.