Water pressure tank (C) Daniel Friedman InspectApedia.comWater Tank Diagnostic FAQs
Problems with the water pressure tank or water storage tank trace to well pump complaints

  • WATER TANK DIAGNOSTIC FAQs - CONTENTS: FAQs about problems with the water pressure tank or well water tank that might actually explain problems blamed on the well pump.
  • POST a QUESTION or READ FAQs about diagnosing problems with the well water pressure tank or water storage tank that show up as pump operating problems
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Water tank diagnostic FAQs:

this article provides answers to frequently-asked questions about how to diagnose problems with the water pump or tank supplying building water pressure & flow.

These questions help sort out the causes of water pressure problems and help determine if the problem appears to be at the water pump, water pressure tank, water piping, or water source such as a private well or water storage tank.

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Well Tank Problems, Trouble With Water Pressure Following Water Pressure Tank Replacement or Relocation, etc.

Photograph of a sketch of a water pressure tank in cross sectionHow might a bad water pressure tank be related to water pressure or water supply loss symptoms

[Click to enlarge any image]

Question: my water system has a pump but no pressure tank, now my pump is losing pressure ...

I don't have a tank so the water comes out by the pump so the pump runs the entire time I use my sprinkers. The pump runs but doesn't seem to run as high as it usually sounds so my water doesn't keep coming out. Do I need a new pump? I replaced it 4 years ago. - Debbie 4/16/12


Debbie, if you run a well pump with no pressure tank to make the pump's life easier, you have to expect a reduced pump life. Your pump may have a worn internal bushing, damaged impeller, or a similar mechanical part damaged. SPECULATING, I could imagine also that the rapid on-off cycling of the pump (that's what typically happens if you run a pump on a water system with no pressure tank) might have even burned electrical contacts on a switch. Normally I'd expect the switch to just top working, but maybe instead you're seeing increased resistance and/or low voltage in the system.

Question: We relocated our water pressure tank and now can't get any water - what's wrong?

We moved our fresh water tank at the cabin from our driveway above the cabin to under the cabin. The pump has always been located under the cabin. Now the tank sits a few feet below pump level and we cannot get water to the cabin. The tank water level is slightly below the pump. - Pat

Reply: Provided the water pressure tank is not too high above your jet pump the problem is not moving the tank it's more likely a plumbing mistake or pump/pump control problem.

Pat: even a one line jet pump can lift water about 25 feet. So I suspect your pump needs replacement. If that's not the problem then it's lost prime or there is another issue.

Question: Water pressure at shower drops and water temperature varies just after we replaced our bladderless steel water tank with an internal-bladder model

I just replaced my old style steel cold water tank with a pressurized tank. I have a 40-60 jet pump that worked fine with the old tank. Now, when the I turn on the water at the shower, when the pump gets to 40 psi, the pressure drops way off and the water temperature oscillates between hot and cold. The system did not do this before I put in the pressurized tank. - Mike Barber

Reply: Things to check when water pressure behavior is odd following water tank replacement

Mike, This is an tough water pressure diagnosis question for which I have to guess at some things that are worth investigating further, as I'm not sure exactly what's wrong.

Check the operating pressure cycle of the pump and tank system by running water while watching the pump, tank, and pressure gauge.

Note the gauge pressure at which the pump cuts in and out. Typically the range is 20/40 or 30/50 cut in and cut out.

Assuming your pump pressure control switch is set (factory) to 20/40, if the the pressure gauge reads 40 just when the pump cuts OFF then the pressure, switch, and system look normal - so far. (If you run water too fast at a nearby fixture the pump may never reach its cut-off pressure, in which case once the pump is running then turn off the water running in the house so we can see the cutoff pressure).

Watch out: debris or other problems can lead a water pressure gauge to give inaccurate water pressure readings. Try tapping gently on the gauge if it is not responding to the pump turning on and off, and see WATER PRESSURE GAUGE ACCURACY for details.

If the pump cuts off at 40 as above and the gauge reads 40, you should have a fully pressurized water pressure tank with a normal dose of water in the tank. You can confirm this in part by gently rocking the water tank - it should be heavy and not move easily. Don't push around so much as to move pipes and start a leak.

Now turn ono water at the shower. If you do NOT have good water pressure and flow, then I suspect that there is a blockage somewhere in the system. Check pressure and flow at other fixtures. If ALL plumbing fixtures have poor flow, then the blockage is at or close to the water pressure tank.

Some pressure tank bladders can sometimes stick or collapse or tear, interfering with water pressure leaving the tank. Under the conditions above, if the pressure in the house is poor at pump cut off I suspect that may be the problem and some tank diagnosis, a tank installation problem, or a tank bladder defect are worth pursuing. A Minnesota plumber told me they sometimes free up a stuck tank bladder by briefly holding the pressure switch down to force tank pressure 10-20 psi above normal

Watch out: excessive water tank pressure beyond its design pressure can burst the tank and injure someone. This is particularly true if no one installed the necessary pressure relief valve at the water pressure tank. See WATER TANK RELIEF VALVE

If the water pressure drop is just at the shower I suspect debris blocking at the shower head or piping.

The fluctuating "hot and cold" temperature is another important clue to consider.To me that suggests that cold water flow in the whole system has at that point become intermittent but not through the entire system.

By that I mean if pressure leavinvg the water tank were itnermittent then because cold water is flowing BOTH to the hot water tank (where it pushes hot water out to the plumbing fixture) AND to the cold water deliver lines in the home, THEN both hot and cold pressure would fluctuate together (I'd think), so the water pressure would vary at the shower but the temp would vary less as hot and cold are both flowing through the whole system at same rate.

The implication of the case you describe (temperature varies significantly at the shower) implies to me that cold water is being blocked somewhere else than right at the water tank - because you're seeing more cold flow blockage than hot flow blockage.

Another reader found a solution to this problem at a debris block in a piping elbow in a cold water line.

Finally, if your pump pressure control switch is not behaving properly, say not turning on the pump at the CUT IN when it should, I suspect that there may be debris blocking at the pressure control switch. Sometimes changing out a water pressure tank can stir up debris in the whole water supply system, exacerbating a problem with the pump pressure control switch or piping.

This problem is more likely if the water supply suffers from clay or silt or other debris or if the building piping includes rusty iron pipes. A solution is to check and perhaps replace both the pressure control switch and the small diameter pipe nipple that mounts the switch body to the building water piping or pressure tank.

Please look into these possibilities and let me know what you're finding - what you learn will help other readers. And I'll think about and research this question further and add what else I can come up with.

Reader Follow-up from Michael Barber

I finally have gotten the time to get back to my water pressure problem. I replaced the old style steel tank with a "bladder" tank.

My pump is a 40/60. I opened the drain line (I added this to the main cold water line going into the house so I could run the water from under the house where the pump and water tank are) and have set the pump pressure switch so that it shuts off at precisely 60 psi and starts at 40 psi.

With the water line open the pump turns on right at 40 psi, then the pressure drops rapidly to about 20 psi and then slowly drops to between 8 and 12 psi where it stays until I close the water line. I set the tank pressure at 38 psi with the pump off after having drained the line.

When I use the shower, or any other faucet for that mater, the pressure is great for the first 3 to 3.5 mins but then drops off significantly and only partially returns to full pressure (consistent with what I see on the gauge under the house).

The problem I am having is that the water pressure did not act like this prior to replacing the tank.

Is this normal for these types of tanks? If so, should I just have my old tank welded up a reinstall it? I posted this on the site a few days ago but haven't had a response. At least that I could find. Thanks, - mike barber


Thank you for the added details. Below I offer some diagnostic suggestions and comments:

Steady state water pressure at maximum flow rate:

It is normal for the water system pressure to remain at a much lower number (8-12 psi in your case) than the pump pressure control switch cut-off number (60 psi) when you are running a faucet and pipe wide open; The pressure you are seeing is the steady-state water pressure that the pump is capable of delivering continuously - a function of the pump horsepower, total lift, pipe lengths, diameter, bends, and other obstructions.

Steady state water pressure at single fixture flow rate:

When you do not have any other plumbing faucet wide open but are running a single fixture such as a shower or sink, and when you report good pressure for the first three minutes, most likely that pressure is being delivered by the water pressure tank that is starting at 60 psi and falls to 40 psi when the pump then turns on.

After that point we have exhausted the stored energy/pressure in the water pressure tank. Thence the water pressure we see in the system is strictly the pressure capability of the pump and piping properties I outlined just above.

Improving steady state water flow rate & pressure:

When the single fixture (or for that matter even multiple fixture) water flow rate is inadequate there are some things to check to fix the trouble. If the poor water system steady state flow rate/pressure has been present since installation or for a long time or developed slowly over months or years, we suspect limitations due to

see WATER PRESSURE PROBLEM DIAGNOSIS TABLE linked-to in the article above for a more complete list of diagnostic suggestions

When a poor water flow rate and pressure problem has developed suddenly we suspect:

Keep in touch - what you find will help other readers. - Daniel

Question: we have a driven point well with a pump that won't stop running until I turn off the water

I live in a mobile home with a point well system (2"). Today the pump kept running while I was sprinkling the garden. It did shut off when I turned the water off. Usually it cycles on & off while the water is running. Any suggestions? - Sharon 8/31/ 12



When a well pump keeps on running - just won't stop on its own, you will want to follow the well pump diagnostic steps at WATER PUMP WONT STOP RUNNING. (Search InspectApedia for that title if necessary)

When the well pump stops running when you turn off the water, then the problem is not likely to be the pressure switch, and more likely is instead a problem with the ability of the pump to deliver water fast enough for your usage rate. Since the pump used to be able to "get ahead of" your water demand when the only thing you were doing was running a garden sprinkler, here are some things to check:

Question: Submersible well pump giving a big drop off in pressure, recovers only briefly, good pressure at the water filter cleanout valve

I have an in well pump, and what I'm getting is a big drop off of pressure in the house. It recovers after a while but does not last long ( bout a minute)then its just a trickle. I get good consistant pressure on the filter clean out valve but not in the house. When water is running in the house, the pump cuts on & off while water is running but never the pressure it should.. Any ideas would be appreciated - Rob 9/4/12



Rob it sounds as if your water filter may be clogged. Or the valve that temporarily bypasses or shuts off the water filter (to allow service) may be damaged, shut, improperly set. Also check for a waterlogged pressure tank - lost air charge.

Question: water pressure cycles between strong and weak; can it be the pressure tank?

i have a ground pump and of late i've noticed my toliets when flushed make a fill pause fill pause fill sound. Today i showered and could fill the water pressure strong and weak, then go strong again?

Can you tell me if it is the pressure tank under my house or the under ground water pump, which i replaced the wiring to the pump with the pipes. We do not know how old the pump or pressure tanke are. This house is at least 18 years old. any comments or suggestions would be greatly appreciated. How do i know when i need a new pump? It is a 3 ft wide, 80 ft. deep well? Please any comment would be greatly appreciated. Thank you so much a concerned mother of 2 youngions :) sk - Suzette Kerr 9/13/12


Suzette, it sounds like a waterlogged water pressure tank.

Search InspectAPedia for the article title SHORT CYCLING WATER PUMP using the search box just above to diagnose and fix the problem.


The pressure sensor on my water pump has a rubber cap. There is a little drip from the small tip which accumulates in the rubber cap. Now I am loosing water pressure to 10 instead of the usual 30-50. I removed the rubber cap and re-seated it with return of the pressure but I am sure this is not a permanent fix as the leak is still there. What do I do now?? - Sandra 9/25/12



Tell me the brand and model of switch so that we can review the manufacturers specs, and send me a photo of the drip problem el that I better understand where water is coming from.

Question: Issues with well water system: noisy pump, humming, pump keeps running;

Over the last few days I have had a few issues with our well after system.
Initial symptoms was a noisy pump (droning sound through out the pipes... Like hum hum hum hum), constantly running pump ( noticed recently) Reset pump once or twice and system ran quieter for a few days.
Noise returned and reset the switch and noticed the contacts were a little dodgy. A few days later the pump wasn't on (no pressure) and checked the contacts, cycled switch and all returned to normal.

Contacts looked loose so I replaced the switch and checked the pressures again. Noise at the at switch and gauge area where the pump line comes in is still there but not through the whole house. Pressure is 40 cut in 55out. I wanted to adjust the out up to 60psi but noticed the spring had no pressure on it. I drained the system and checked the tank static charge pressure and it was very low. Went and bought a little air pump and charged to about 38psi. Checked operation and it functions well but noticed the pressure cut out is still 55, (played with cut out and still 55) and pressure drops off fast.

At this point I am still suspecting the check valve but I don't see it by the switch, I thought I would see an obvious fitting that has a direction arrow or something to denote a check valve.... Maybe on pump? So either pump or check valve with pump running all the time and not reaching 60 psi?

This morning no tap pressure or flow, pump shows 20psi. I flicked the switch on and off to the pump and the pump fired up, built pressure to 55 and cut out. After a few cycles the pump I'd back to running all the time and not kicking out at all... Runs about 50psi. Just short of cut out of 55 that it was previously cutting out at which should be 60 but I can't adjust the cut out up as the pressure isn't going that high and I can't lower it to cut out at lower pressure as the pressure is lower than what the minimum pressure cut out setting can be.
It held pressure. So pump runs all the time, and doesn't build pressure past 50.
Pump failing? - Chris 9/26/12


I don't fully get the picture, but offer that

- you can for the moment set the cut in to 20 and cut out to 40 psi so the pump should be able to reach the cutoff pressure.

- several problems can cause the pump to keep running (search InspectAPedia for

Pump won't shut off

Examples are a damaged pump impeller, a well with poor recovery rate, and a leal in well piping

Reader Follow-up:

Hi Dan,
The pump isn't reaching the minimum pressure for the max setting to be set. The low setting has a min and max setting it will work at and so does the max side. The issue here is that the pump does not reach the lowest setting the cut out high side works at. It must be about 55 is as low as the cut off setting will go.

Today the pressure was bad again and was around 20psi. I turned off the pump and turned it on again and it went up to about 40psi..still too low to set the cut out pressure.... Enough to have a shower though :)

I will say when the pump is turned off the water in the pressure tank empties. You can hear it...and it's odd that when I turn it back on again the pressure runs higher.
Maybe by switching it off, the water runs back through the check valve and pump and washes the impeller or valve clear?
I have read the section you refer to but not sure the symptoms are consistent.
I don't think a leak is the issue as switching the pump on and off shouldnt change the pressure..especially increase it.
Not sure a failing pump would either but it might be weak?
A stuck open or partially open check valve sounds right? Are these on the pump as I don't see it by with switch?

Maybe I could lower the cut in pressure and that would lower the cut out min pressure too?
So I go switch it on and off a few times and it builds back to 55psi and holds pressure for 30 seconds or so(that's long for this system) and cuts out.
Do that once more and only build to 40 and keeps running. Weird.

Time to call the guys who service and installed the system and see what they say.



For now I would lower the cut-out pressure to be sure the pump won't burn itself up; but we need to find why the pump doesn't reach cutout pressure and address that. If the cutout is not set to some level that a pump simply cannot reach (say over 60 or 70 psi for some pumps) then more likely the problem is

Question: water pump kicks on immediately every time we turn on the water

pump kicks on every time you turn water on? - Debra 10/2/2012



If the pump turns on immediately whenever you turn on the water at a fixture, most likely the water pressure tank is waterlogged - it has lost its air charge.


We have replaced the pump switch recently, and the problem is getting worse if two things are running at the same time (i.e. toilet flush and washing machine) the pump(?) won't catch (when it hits the certain spot it's supposed to) and we have to manually go downstairs and reset it to get the water going again. What is the problem?? Please help before this problem gets worse!!!



Check for a debris-clogged sensor orifice on the pump pressure switch OR a debris-clogged tube that feeds water pressure to the switch.

Question: Water pressure stopped for 20 seconds at a time - problem traced to iron-clogged pressure switch; is this a water quality issue or a wear and tear issue?

We had an issue with water pressure ( water would stop flowing for 20 sec at a time) in a house we are renting. The owner called the local well drilling co. They replaced the pressure switch which was clogged with iron. Is this a wear and tear issue or a water quality issue or something else. - Sue - 9/7/2012


Sue, thanks for the important question - it gives us a chance to clarify the problem with debris clogging at well pump pressure control switches and pressure gauges.

Debris in the water supply or sometimes rust in water piping can clog the small pressure sensor port on the bottom of a pressure control switch, causing it to fail to operate properly - that is, the debris prevents accurate sensing of actual water pressure so the switch may fail to turn a pump on or off as it should. In the "turn-off" case the result could be very dangerous as overpressurizing the water system could burst a pipe or even a pressure tank, injuring a bystander and flooding a building.

Similarly, the same problem can cause a water pressure gauge to fail to properly register water pressure accurately. Often we can detect this by tapping the gauge and seeing its pressure reading suddenly change, after observing that the gauge reads an abnormally low pressure or when the gauge pressure reading simply doesn't change.

While these problems can be repaired by replacing the clogged pressure control switch or pressure gauge, the root problem is debris or rust in the system - a problem that can be addressed by installing water filtration ahead of these components.

So in response to your question, the underlying problem is a water quality problem combined with inadequate water filtration, not a wear and tear issue - in my OPINION


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