Water Pump Won't Turn Off: 7 Causes and How to Fix It

Written by Fajar Webarq. Updated October 26, 2026.

Summary

• An automatic water pump should shut itself off as soon as the pressure in the pipe reaches the upper limit. If it keeps running, that pressure is never reached or the sensor is not working.
• The most common cause is outside the pump: a leaking faucet, pipe or toilet. Check this first, because it is the easiest and cheapest fix.
• A pump that keeps running without drawing water can damage the seal and the motor. Switch it off before you inspect anything.

A water pump that won't turn off almost always comes down to one of two things: the water pressure in the pipe never rises to the cut-off point, or the pressure switch fails to read that pressure. This guide orders the checks from what you can do yourself in five minutes to what is best left to a technician.

Why Does an Automatic Water Pump Keep Running?

A household automatic pump is controlled by a pressure switch that turns the pump on when the pressure falls below the lower limit and turns it off when the pressure reaches the upper limit. If the pressure never reaches the upper limit, because water is leaking, the pump cannot push hard enough, or the sensor is clogged, the pump keeps running.

For reference, the Shimizu PS-255 BIT manual lists a factory setting of 1.4 kgf/cm² to switch on and 2.2 kgf/cm² to switch off. These numbers differ by brand and model, so check your own pump's manual. The principle is the same and is also explained in a community service journal from the University of Mataram (2025): as long as the pressure has not reached the upper limit, the switch will not cut power to the motor.

Pumps with electronic control or a flow switch work slightly differently. The manual for the Shimizu SC-015 E controller names a faulty electronic component, a blocked detector and a faulty float as causes of a pump that keeps operating.

Table of Causes When a Water Pump Won't Turn Off

Use this table to match the symptom you see with the likely cause.

Causes 1, 2 and 7 are listed in the Shimizu PS-255 BIT manual as reasons a pump operates even when no faucet is open. Causes 3 and 4 appear in the troubleshooting table of the same manual. Dirt buildup on the pressure switch (cause 5) is cited by Grundfos. Stuck contacts and a leaking foot valve that causes the pump to lose its prime are described on InspectAPedia. A clogged impeller or nozzle (cause 6) is mentioned in the Everbilt pump manual (2024).

Diagnosis Steps, Easiest First

The order below starts with checks that do not require opening the pump. Stop at the step that finds the problem.

1. Make it safe first. Unplug the pump or switch off its MCB (circuit breaker). Before you open the pressure switch or a pipe joint, release the pressure in the system by opening one faucet until water stops flowing, as Grundfos advises. Water and electricity are a dangerous combination, so make sure your hands and the floor are dry.
2. Test for leaks by closing every faucet. Switch the pump back on, close all faucets, and wait until the pump stops. If the pump starts again a little later with nobody using water, there is almost certainly a leak. Check the toilet tank (listen for running water), the garden faucet, the pipe joints in the wall and the float in the water tank.
3. See whether water comes out normally. A pump that runs but delivers little or no water usually has an air lock or has lost its prime. This often happens when the foot valve at the end of the suction pipe leaks. Refill the prime following your pump's manual, then watch whether it is lost again.
4. Consider the well's water depth. Shallow-well jet pumps generally have a maximum suction of about 9 meters, for example the Shimizu PS-221 BIT and the Panasonic GA-126JAK. That limit is theoretical; Process Engineering notes that the practical limit is lower, around 7 to 8 meters. If the problem shows up in the dry season, the water level has probably dropped below the pump's reach.
5. Clean the check valve. The Shimizu manual advises cleaning dirt out of a check valve that does not close tightly. Do this only after the power is off and the pressure has been released. If you are not sure where it is, skip this step and note it for the technician.
6. Inspect the pressure switch. Open the cover and look for dirt, rust or burn marks on the contacts. The small hole that connects the switch to the pump housing can clog with sediment, so the switch does not "feel" the pressure. Contacts that are stuck or burned are best replaced by a technician, not improvised around.
7. Watch the pressure with all faucets closed. If the pump has a pressure gauge and the needle never reaches the cut-off point, the pump's output has probably dropped, for example because the impeller or nozzle is clogged. This check requires taking the pump apart, so leave it to a technician.

A Water Pump That Cycles On and Off: A Different Problem

A pump that switches on and off repeatedly within seconds (short cycling) is a different problem from a pump that never switches off. The most common causes are a pressure tank that has lost its air charge or has a ruptured diaphragm, small leaks and leaking valves. The K2 Pumps guide says the tank's air pressure should be set 2 psi below the cut-in point, measured with the power off and the water drained.

A small leak can also cause this pattern. The Shimizu SC-015 E controller manual says a leak below 0.6 liters per minute makes the pump cycle on and off often, while a leak above that figure makes it run constantly. We cover this symptom in more detail in our article on a water pump that keeps turning on and off.

The Risk of Letting the Pump Keep Running

A pump that keeps running, especially without drawing water, risks damage and wastes electricity. The Shimizu manual asks users to avoid letting the pump run for long periods without drawing water because it shortens the pump's life. Grundfos explains that running dry can damage the mechanical seal and the motor.

Many household pumps have a thermal protector that cuts the motor when it gets too hot. The Shimizu PS-255 BIT manual advises waiting 20 to 30 minutes until the motor cools. The UNRAM journal also notes that on-off cycles that are too frequent waste electricity and wear out the motor and seal faster.

When to Call a Technician

Call a technician if any of the following happens:

• Water seeps from the pump body near the motor, which indicates a leaking mechanical seal.
• The pressure switch contacts look burned, melted or stuck.
• The pump smells burned, makes a rough noise, or its thermal protector keeps cutting the motor.
• The pump's power cable is damaged. The Shimizu manual states that replacing the supply cable must be done only by the factory, a service center or a qualified person.
• You have already worked through steps 1 to 5 and the pump still won't turn off.

How to Prevent a Water Pump That Won't Turn Off

Simple maintenance lowers the chance of this problem coming back:

• Check for leaks regularly with the faucet-closing test in step 2, especially if the pump starts coming on more often with nobody using water.
• Clean the strainer and valves regularly, especially if your well water is sandy or chalky.
• Keep the pump protected from rain and direct heat, with enough air circulation around the motor.
• Watch for seasonal changes. In the dry season, notice whether the water starts coming out weakly, because that is an early sign the well's water level is dropping.

Frequently Asked Questions

Why does my water pump keep running when nothing is using water?

Most often there is a leak that keeps lowering the pressure in the pipe, such as a dripping faucet, a cracked pipe or a toilet that keeps running. Close all faucets and see whether the pump still runs. If it does, trace the leak before you inspect the pump.

How do I fix an automatic water pump that won't turn off?

Switch off the power, release the pressure, then check in order: leaks, the prime and the foot valve, the check valve, and then the pressure switch. The full steps are in the diagnosis section above. Repairs to the switch contacts and seals are best done by a technician.

How many hours can a water pump run at most?

The manufacturers we referenced do not list a standard limit in hours. A household automatic pump is designed to run only when water is being used. If the pump keeps running with nobody using water, switch it off and look for the cause, and do not wait for the thermal protector to kick in.

Why does the water pump run but no water comes out?

Usually the pump has an air lock or has lost its prime, the foot valve is leaking, or the well's water level is below the suction limit. Refill the prime and check the suction pipe for air leaks.

Can I fix a faulty pressure switch myself?

You can clean dirt from around the switch and its sensing hole with the power off. Burned or stuck contacts are best replaced by a technician, because this is part of the pump's electrical system.

Next Steps

If the problem is a prime that keeps getting lost, read why a water pump needs constant priming. All of our pump maintenance guides are in the Home Water Pump Maintenance Guide.