How to Tell If a Well Pump Pressure Switch Is Bad

Gemma Johnstone
Written by Gemma Johnstone
Updated October 29, 2021
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If your well water supply suddenly runs dry, it might be a vital but straightforward mechanical part that's causing the problem

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If you’re a part of the 15% of the U.S population that uses a domestic well for your water supply, something as simple as a degrading well pump pressure switch can cause serious problems. It can cause a loss of water pressure or even cut off your water supply altogether. Learn how to tell if your well pump pressure switch is bad and whether it needs replacing.

What Is a Well Pump Pressure Switch?

The pressure switch signals to the well pump when it needs to start or stop pumping water. It does this based on the built-up pressure in the water system. The switch typically has the following range of numbers: 20–40, 30–50, 40–50. These relate to the pound per square inch (psi) pressure levels. 

When the pressure drops to the lowest “cut-in” number, the pressure switch will turn on, and the pump will fill your tank. It’ll switch off and stop pumping when it reaches the highest “cut-off” number. You can adjust the low and high numbers to any of the three setting options depending on your home's water supply needs.

Where Is the Well Pump Pressure Switch Located?

Locating your well pump pressure switch will be your first challenge; its location can vary depending on the type of pump and your home setup. You’ll usually find the switch on the side of a jet pump. However, you’ll find the covered switch’s location elsewhere if you have a submersible pump. Typically, you’ll find it in the basement, garage, or somewhere in your yard, sometimes mounted on a small tube near the pressure tank.

Reasons for Well Pump Pressure Switch Failure

The pressure switch comprises a simple internal spring mechanism connected to a set of electrical contacts. Over time, the spring weakens, parts clog with debris, and the electrical contacts corrode and degrade. Even though the switch usually has a sturdy cover, humidity and frequent use all play their part in the inevitable wear and tear of this simple piece of equipment.

Signs Your Well Pump Pressure Switch Is Failing

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Some common indications that there could be a problem with your well pump pressure switch include:

  • The pump doesn’t turn on, even though the water pressure has dropped below the set cut-in point.

  • The pump isn’t turning off, even though the water pressure has gone beyond the set cut-out point.

  • Your water pressure is low, despite the pump running

  • The pump switches on and then off again immediately.

These problems can also indicate more serious issues with your well water system, like a broken pump, leakage in the system, or a decompressed pressure tank. If you can’t spot any obvious problems with the pressure switch, it’s best to call out a well pump repair service near you. They’ll diagnose the problem and carry out any repairs or replacements required.

Troubleshooting Well Pump Pressure Switch Problems

Before you call out a professional, there are some simple troubleshooting steps you can try first. For safety, make sure you cut the power supply to the well pump system off in advance. To inspect the inner workings of the switch, you’ll need to remove the plastic covering.

Check for Electrical Connection Problems

Before turning off the power, bang a screwdriver handle against the tube the well pump switch is on. If you notice a spark or the pump powers back on, this could be a sign of problems with electrical connections in the pressure switch.

The contacts can corrode, bugs or debris can get trapped between them, and they also wear down with continual use. With the power turned off, it’s possible to pull the contacts open and gently file down any corroded section with a nail file. This may be enough to get the switch working again as a temporary fix while you wait for a professional to come out to make a full replacement.

Unclog the Pressure Sensor

Water sediment and iron bacteria can build up in the switch's pressure sensor. You can clean the tube that connects your switch to the water supply with the power turned off.

Check for Leaks

Water can sometimes leak into the switch housing and mechanisms. If this has happened, turn off the electricity immediately and arrange for a replacement switch. If the water leaks under the switch at the plumbing connection, it may be possible to tighten this and resolve the problem.   

Sometimes leaks elsewhere in your home or in the pump system can cause a loss of pressure. Look out for signs of pooling water.

Check the Water Pump Cycle

If the internal spring has become too loose, this can stop the switch from working, requiring replacement. To check the spring’s tightness, open a water faucet and let the pump complete a full cycle. If the switch doesn’t turn on, this could be a sign there’s a problem with the spring.

Can I Replace a Faulty Well Pump Pressure Switch Myself?

New switches aren’t expensive to purchase, but you should only attempt to replace one yourself if you’re confident with electrical components, the power is off, and you’re sure it’s the problem-causing switch. Pressure switch replacement is an easy, fast, and inexpensive repair for a pro compared to the complexity and cost of a complete well pump replacement.

If you aren’t certain the switch is causing your well pump pressure problems or you’ve replaced the switch and problems persist, call in a local professional. Well pump problems are often wide-ranging, complex, and best left to the pros to diagnose and resolve.

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