Test your well pump in place using water pressure, flow rate, and electrical checks
You can diagnose many well pump problems without hiring a contractor to pull the pump from the well. The most useful tests measure water pressure at your house, check how much water flows from a faucet, and verify that power is reaching the pump. These three checks catch the majority of common failures — low pressure, weak flow, and electrical shutdowns — and tell you whether the pump itself is the problem or something else in your system.
The tests take 15 to 30 minutes and require only basic tools: a pressure gauge (under $20), a bucket, a timer or phone stopwatch, and a multimeter if you want to check electrical connections. If the pump passes these tests, the problem is usually in the pressure tank, check valve, or plumbing lines rather than the pump itself.
Key Takeaways
- Water pressure at your house should read between 40 and 60 pounds per square inch (psi) when a faucet is open; pressure below 30 psi or above 80 psi suggests a pump or tank problem.
- Flow rate tells you whether the pump is delivering enough water — measure how many gallons fill a bucket in one minute from a single faucet.
- A multimeter can confirm that 240 volts is reaching the pump's electrical box, which rules out a tripped breaker or loose wire before you suspect pump failure.
- Pressure tank problems and check valve failures often mimic pump failure, so test the tank and valve before concluding the pump needs replacement.
- YouTube videos showing pressure gauge installation and flow testing are useful references, but the actual test takes only minutes once you have the right gauge.
How to measure water pressure at your house
Attach a pressure gauge to the lowest faucet in your house — usually a basement or outdoor spigot — while the pump is running and no other water is being used. The gauge screws onto the faucet outlet in place of an aerator or hose. Turn on the faucet fully and read the pressure. Normal pressure is 40 to 60 psi. Pressure below 30 psi means weak flow throughout the house. Pressure above 80 psi can damage fixtures and indicates the pressure tank is not working correctly.
If pressure drops suddenly while the faucet is open, the pump may be failing to keep up with demand. If pressure stays steady but is too low, the problem could be a weak pump, a clogged intake line, or a check valve stuck partially closed. If pressure is too high, the pressure tank's air bladder may have lost its charge, or the pump's pressure switch may be set incorrectly.
Write down the pressure reading and the time of day. Test again the next time the pump cycles on — you should see pressure climb from the cut-in point (usually 30 to 40 psi) to the cut-out point (usually 50 to 60 psi). If the pump does not cycle on at all, check that the breaker is not tripped and that power is reaching the pump's electrical box.
Check water flow rate from a single faucet
Flow rate tells you how many gallons per minute the pump is delivering. Turn on a single faucet fully — use an outdoor spigot or a kitchen sink — and fill a bucket while timing how long it takes. A 5-gallon bucket should fill in 30 to 60 seconds for a typical household pump. If it takes longer than 90 seconds, the pump is delivering less than 3 gallons per minute, which is below normal for most residential wells.
Low flow can mean the pump is failing, but it can also mean the intake line is clogged, the check valve is partially stuck, or sediment is blocking the well screen. If pressure is normal but flow is weak, the problem is usually downstream of the pump — in the plumbing or check valve — rather than in the pump itself. If both pressure and flow are low, the pump is more likely to be the source.
Test flow rate at the same time each day for three days. If flow drops over time, sediment may be accumulating in the well or the pump intake. If flow is consistently low, the problem is likely permanent and not a temporary blockage.
Verify electrical power is reaching the pump
A multimeter can confirm that 240 volts is reaching the pump's electrical box. Turn off the breaker to the pump before opening the box. Set the multimeter to measure AC voltage (usually marked with a wavy line and "V~"). Turn the breaker back on without closing the electrical box. Touch one probe to each of the two hot wires inside the box — the meter should read approximately 240 volts. If it reads 0 or much lower, the breaker may be tripped, the wire may be loose, or the disconnect switch may be off.
If the meter reads 240 volts but the pump is not running, the problem is inside the pump or its control box, not in the house wiring. If the meter reads 0 volts, turn off the breaker, check that all wire connections are tight, and turn the breaker back on. If voltage still reads 0, the breaker itself may be faulty or the main panel may have a problem.
Do not touch the wires themselves or work inside the electrical box if you are not comfortable with electricity. A licensed electrician can perform this test if you prefer.
Test the pressure tank and check valve
The pressure tank stores water under pressure so the pump does not run every time you turn on a faucet. Over time, the air bladder inside the tank can lose its charge, causing the pump to cycle on and off too frequently or pressure to drop quickly after the pump shuts off. You can test this by turning off the breaker to the pump, opening a faucet to drain the tank, and listening for air to hiss out. If no air comes out, the bladder has failed.
A check valve prevents water from flowing backward into the well when the pump shuts off. If the check valve is stuck or leaking, pressure will drop quickly after the pump stops, and the pump will restart frequently. You can hear this as rapid on-off cycling. To test, turn off the pump and watch the pressure gauge. If pressure drops more than 10 psi in the first minute, the check valve may be leaking.
Both of these problems mimic pump failure but do not require pulling the pump. A failed pressure tank bladder can be recharged or replaced by a technician without removing the pump. A stuck check valve can sometimes be cleaned or replaced at the wellhead.
Interpret your test results
Use this table to match your test results to the most likely cause:
| Pressure | Flow | Pump Cycles | Most Likely Problem |
|---|---|---|---|
| Normal (40–60 psi) | Normal | Normal | System is working. No pump problem. |
| Low (<30 psi) | Low | Runs constantly | Pump is weak or intake line is clogged. |
| Low (<30 psi) | Normal | Normal | Check valve is stuck or leaking. |
| Normal | Low | Normal | Plumbing line is clogged or check valve is partially stuck. |
| Drops quickly after pump stops | Normal while running | Cycles frequently | Check valve is leaking or pressure tank bladder has failed. |
| High (>80 psi) | Normal | Normal | Pressure tank bladder has failed or pressure switch is set too high. |
| 0 volts at electrical box | No flow | Does not run | Breaker is tripped, wire is loose, or main panel has a problem. |
If your results match the first row, the pump is working correctly and you do not need further testing. If your results match any other row, write down which test failed and share that information with a well technician. This narrows the diagnosis and can save you money on service calls.
Common mistakes when testing a well pump
Do not test pressure while other water is being used in the house — a shower, washing machine, or outdoor sprinkler will lower the reading and give you a false result. Turn off all water use and wait at least five minutes before attaching the gauge. Do not leave the pressure gauge attached to the faucet permanently; remove it after testing to avoid damaging the gauge or the faucet.
Do not assume low pressure means the pump is failing. Low pressure with normal flow usually points to a check valve problem, not the pump. Similarly, do not assume rapid on-off cycling means the pump is broken; it often means the pressure tank has lost its air charge, which is a much cheaper fix.
Do not work inside the electrical box unless you are trained to do so. If you are uncomfortable checking voltage, hire an electrician. A mistake with 240-volt wiring can cause serious injury.
When to call a professional
If your tests show that pressure and flow are both low and the pump runs constantly, a well technician will need to pull the pump to inspect the intake and impeller. If tests show normal pressure and flow but the pump does not run at all, an electrician should check the wiring and control box. If the pressure tank or check valve is the problem, a technician can usually fix it without removing the pump.
Before calling for service, have your test results ready — pressure reading, flow rate, and whether the pump cycles normally. This information helps the technician decide whether to pull the pump or start with a cheaper repair.
Frequently Asked Questions
What pressure gauge should I buy?
Buy a glycerin-filled pressure gauge rated for 0 to 100 psi, available at any hardware store for $15 to $30. Glycerin dampens needle vibration and makes the reading easier to see. Make sure the gauge has a female NPT thread that fits your faucet outlet. A 1.5-inch dial is easier to read than a smaller one.
Can I test the pump if the power is off?
No. The pump must be running to measure pressure and flow. Turn the breaker on and let the pump cycle normally. If the pump will not turn on, check that the breaker is not tripped and that the disconnect switch is in the on position before testing voltage.
How often should I test my well pump?
Test pressure and flow once a year, ideally in spring after winter use. If you notice changes in water pressure or flow, test when ready. Rapid testing can catch problems early and prevent a complete pump failure.
What does it mean if the pump cycles on and off every few minutes?
Frequent cycling usually means the pressure tank has lost its air charge, the check valve is leaking, or the pressure switch is set too low. It is rarely a sign that the pump itself is failing. A technician can recharge the tank or replace the check valve without pulling the pump.
Can YouTube videos replace these tests?
YouTube videos are useful for learning how to attach a pressure gauge and what normal readings look like, but they cannot replace the actual measurements from your own system. Your well pump, tank, and plumbing are unique to your house, so your own test results are what matter for diagnosis.