Water pressure control adjustment nuts (C) D FriedmanUsual Water Pump and Tank Pressure Control Settings
What are the usual pump-on and pump-off pressure settings for a well water pump?

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Standard settings for a well pump pressure control switch:

This article describes how to adjust building water pressure by setting the water pump cut-in and cut-out pressure on the well water pump pressure control switch.

We also point to our article on how to adjust building municipal or community water pressure at a building.Contact Us by email if you are having trouble finding the information you need.

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What are the Usual Water Pump and Tank Pressure Control Settings in PSI?

Most residential water systems using a water pressure tank and water pump use one of these two pressure operating ranges:

Low-pressure operating range pumps like low horsepower pumps and many jet pumps

Higher-pressure water pumps, like submersible pumps, and higher horsepower 2-line jet pumps

How High Can we Set the Water Pressure in My Building?

You can't just set the pump pressure as high as you want to. Here's what can go wrong with excessive pump pressure control settings:

Reader Question: How can I increase the well pump cut-in pressure without setting the cut-out pressure too high?

Bath tub water flow (C) D Friedman

We have a well and have been experiencing intermittent low water pressure.

I checked the pump and it cuts in at 25 PSI and cuts off at 65 PSI. But the diagram on the inside of the pump switch cover indicates that it should be cutting in at 40 PSI and out at 60 PSI. It has a maximum PSI of 80.

How do I get the well pump to cut in at 40 PSI instead of 25 PSI? I believe this would give us adequate water pressure at all times.

According to the information on your website adjusting the mainspring will change both the cut in and cut off pressures and adjusting the differential will adjust only the cut off pressure. Apparently, there is no way to adjust only the cut in pressure? Thanks for your help. - L.W.

Reply: Here is how to change the cut-in pressure without pushing the cut-out pressure too high

A competent onsite inspection by an expert usually finds additional clues that help accurately diagnose a water pressure or pump problem.

And your cause of inadequate water pressure might be due to more than just the static pressure capability of the pump. For example, the pump's maximum flow rate in gpm could be inadequate, or you could have a partly closed water valve or clogged water pipe. Put another way, many homes that operate between 30 and 50 psi have very good water pressure and flow rate at the fixtures. So if you don't there may be another problem besides the pressure switch settings.

That said, here are some things to consider:

Most pump pressure controls are tricky to adjust in the way you mentioned, but you should be able to set the cut-in to a higher number and then adjust the cut-in - cut-out pressure differential to keep the cut-out pressure from being too high. That will cause your well pump to turn sooner when you start running water (and will cycle it more often, a factor in pump wear).

At PUMP PRESSURE CONTROL ADJUSTMENT we explain that the smaller nut on the pump control switch adjusts the differential or gap between cut in and cut out and the larger nut raises the cut-in pressure (as well as cut off).

In other words you can set the cut in pressure higher and then narrow the differential so that the cut-off pressure is not dangerously high or above what the pump can reach.

Watch out: don't run the water pressure control with too narrow a differential between the cut-in and cut-out or the pump may just sit there short-cycling until you burn up the motor. If your pump is staying on for less than 30 seconds (I prefer longer), you may be heading for trouble.

Watch out: setting the cut-out water pressure too high can cause the pump to never turn off or at high pressures you may find leaks at fixtures. And high water pressure that exceeds the rated water tank pressure can burst the tank - a very dangerous event. Also make sure your pressure tank has a relief valve installed.

Don't Forget to Check For Other Causes of Bad Water Pressure

Clogged copper supply pipes (C) D FriedmanFinally, I suspect that after you have increased the pump cut-in or cut-on pressure to a higher number, say 30 psi, if you will find that this does not fix your water pressure problem.

The fact that your low water pressure is intermittent might in fact point to a problem with the well flow rate itself. (WELL YIELD DEFINITION)

Once the well pump turns on and presuming you are running water continuously, especially if more than one fixture is running, you may see that your pump runs continuously until you turn the water off. If this is the case, it's not the starting water pressure setting that is at fault, it's the pump or piping or well that is limiting the water flow rate.

If I'm right that means that the water flow rate through the system, from well through pump and pipes, elbows, valves, etc. is just not enough, and further diagnosis is in order.

Our photo of copper supply piping (above left) was sent by reader Tom.C. who was tracking down a clog in the supply piping that meant poor water pressure from the point of the fitting you see above onwards through the plumbing fixtures served by that pipe.

Follow-up and Water Pressure Problem Solved:

Looks like I will call a plumber.  I adjusted the mainspring to raise the cut-in/cut-out range but there was no change.

The water pump switch was faulty and had to be replaced.  Also the line going into the water tank was clogged and had to be rodded out.  Working fine now.

The homeowner attempted to adjust the pressure control switch for the water pump. When he turned the adjusting nut the water pump behavior and water pressure did not change. That observation led to calling a plumber who replaced the pressure control switch - which solved the water pressure problem.


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PUMP PRESSURE SWITCH STANDARD (PSI) SETTINGS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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