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Water pump pressure switch (C) Daniel Friedman Dropping Water Pressure FAQs

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Q&A on troubleshooting deteriorating water pressure in buildings:

Questions & answers on the causes of water pressure dropping off after the water pump has stopped

This article series describes how to diagnose slow water pressure loss and erratic well pump behavior. We give a step by step diagnostic procedure for falling water pressure trouble.



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FAQs on slow pressure or loss of water pressure in a building after the pump turns off

Causes of bad water pressure
These questions about diagnosing the cause of a slow fall-off in building water pressure when no water is being run (we think) were posted originally in the article above: WATER PRESSURE FALLS SLOWLY, ERRATIC PUMP

On 2017-07-09 by (mod) re: possible explanation for small pressure drop after the pump stops running

Chun and Mac

I've seen this pressure drop at the end of a pump-on cycle too. When pressure remains steady afterwards we know it's not an actual water leak. Or we think so.

I've always figured it was an artifact of the particular pump, piping arrangement, controls - and not something that I think needs fixing. It's probably nothing to do with the switch - more likely the tank and piping and an air cushion somewhere.

But there is another possibility: a very small pinhole leak in the flexible rubber bladder in the pressure tank may open enough to pass a few psi worth of water at your cutoff pressure - say 50 psi - then as pressure drops even a little - to say 45 psi - the hole closes enough that any remaining leakage is so slow that you don't notice it.

You'll eventually find this problem - if it is what's happening in your case - when over time the water pressure tank becomes waterlogged even though with an internal bladder that should not occur. It will show up as

- pump cycles on and off increasingly frequently even though the water usage rate remains unchanged (in a test case)
- the water pressure tank becomes heavier when tested "empty" - with pump off and all pressure drained from the system via nearby taps the pressure tank has more weight than when new

A less-likely possible explanation is that pressure during pumping is, after the pump stops, converted to an expansion of plastic parts or a tank bladder component that absorbs a bit more of the system pressure.

Also see BOYLE's LAW where we explain P1V1 = P2V2 at constant temperature

On 2017-07-08 by Chun

Mac, same exact thing is happening to me, it drops about 5psi then it stays there everytime it reaches cut off, let me know if you have figured it out

On 2017-04-28 by (mod)

How much does pressure fall? Could there be a toilet tank filling? Could there be a debris clogged, slow-to-respond pressure gauge?

On 2017-04-28 by Mac

The water pressure drops 5 psi every time it stops either at 50 or 60. If I set to 30/50, it stops at 50, then comes down to 45..at 40/60, it stops at 60, but comes down to 55... every time.

At first I thought there was a leak somewhere, but then I noticed the pressure will not keep going down.. i've left it for over 2 hrs and it will not continue to drop once it drops the 5 psi..so maybe there is no leak..
I have replaced the pressure switch and the gauge a couple of times with new ones and different models....same thing... This have driven me crazy for a very long time and I can't figure it out.

Question: Gauge at well shows about 62 when pump stops, then settles down to 59.

(Nov 14, 2014) Tim2014 said:

Drilled Well 16yrs old. Previous owner said 400+ ft. I had a short cycle issue that was resolved by re-pressurizing the tank. Pump now works 40-60 as expected and tank is holding the expected air pressure.

I then noticed a slow leak of water pressure while I was correcting the short cycle. Symptom: Gauge at well shows about 62 when pump stops.

Then settles down to 59. I assume that much play in gauge is ok given it is a $6 part.

Water pressure then slowly drops at a slightly variable rate over hours. 15 lbs-9 hrs, 5 lbs-6 hrs, 7 lbs-6.5 hrs, etc... I can turn off the flow to the house at the well and the well and tank holds water pressure constant at 59 lbs for 6 hours.

That leaves me to believe that the drilled well itself (foot valve, piping, etc..) is ok. I don't see any signs of leakage in my home (no visible water, no toilet leak,etc..), but to make sure, I turn off the water as it enters the house and have similar drop rates in pressure as listed above.

That leaves me to believe I have a slow leak in the yard line between the well and the home. Does that sound right? Of course there is no visible evidence of a leak, and that line crosses the sewage, power, phone/internet and propane gas line before it enters the home as the builder was apparently not a good planner.

Question: My tank at the well is supposed to produce a 5 gal draw down at 40/60. So, if I let the well pump 60lbs then open the faucet at the well and let it run in a bucket until the pump kicks back on, I should expect to fill up a 5 gal bucket? So I did that after 6 hours and had about 2 gals in the bucket

. So, I'm leaking 3 gals in 6 hours correct? I don't know much about this, but I assume if the water pressure drops that the water had to go somewhere even I can't find the leak. I don't understand how air could leak into the system, but I've had several people and couple of articles on this site indicate that air might be leaking into the system. Any comments or suggestions?

Reply:

Tim

In the More Reading links above the article titled AIR DISCHARGE at FAUCETS, FIXTURES gives sources of air leaks into a water system: well piping leaks, snifter valves, etc. are discussed. One of those may be the problem.

A slow leak of water out of the piping anywhere between well bottom and building water equipment can leak both water out and in some circumstances air in to the system. Usually we look first for a bad foot valve or check valve

On 2017-01-26 by (mod) my pressure tank will lose pressure right after the pump turns off.

Sounds like a leaky check valve or foot valve in the well.

On 2017-01-26 by Susan

Had a new well pump installed, now my pressure tank will lose pressure right after the pump turns off. I shut the water to the whole house off and kept the pump to tank valve open, Pressure maintained in tank. Opened house water valve and lost 10 pounds of pressure. No house water running. Toilets are not running. Does this indicate we have some kind of leak in the house or could there be other reasons why we are losing pressure?

Question: pump shuts off then pressure drops

(Mar 28, 2013) janet said:
I have a double line jet pump system. The cut in is 30 and off is 50 on pressure switch. The problem is as soon it shuts off, the pressure drops, takes about 20 minutes then cycles again. We installed a check flow valve at the pump, thinking water was flowing back down to well. That didn't solve it. What could be the problem?

Reply:

Janet,

It should be pretty easy to determine if the leak is in the building, at the pump and water tank, or in the well piping. If you shut off all water entering the building and pressure drops, the problem is not a leak in the building.

If your check valve is absolutely pefect, or if you use a temporary shutoff valve between the pressure tank and pump and the well itself, and pressure drops, there is a leak on the pump and tank side of that valve.

Question: pressure falls after pump shuts off

(Apr 15, 2015) Anonymous said:
the pump pumps water bt when shut off the pressure falls

Reply:

look for a running plumbing fixture first, then a leak in piping

On 2017-05-25 by (mod) - pump won't stop running

Anon

What you describe is a common problem - when I use the InspectApedia website search box above to look for PUMP WON'T STOP RUNNING I find the best diagnostic and repair article on this. Please check out

WATER PUMP WONT STOP RUNNING
at http://inspectapedia.com/plumbing/Pump_Runs_On.php

and then let me know how that works for you and of course ask further questions as needed.

On 2017-05-25 by Anonymous

I have a Gould jet pump. It does not stop running. It brings the pressure up to 50 psi (30/50).

If I shut the emergency shutoff switch off the pressure almost immediately drops to zero. Is it the check valve? I've replaced check valves on the system in the past and the pump would be cycling quickly on and off.Mike

On 2017-03-31 by (mod) re: water pressure too low at faucet

James I don't really understand the specifics of what is installed to provide your water supply and pressure. You may need to install a water pressure boosting pump there are also other steps that will increase the water pressure at a building. Please use the search box just above to search inspectapedia for

Increase water pressure

On 2017-03-30 by James

We have a personal water tank in the country, which gets pumped every 3 days to refill.

However, the problem is that while trying to use a shower or the forcet, the water pressure seems to be low. What can be done about it? The shower does not have much force and the tank is about 20ft high from the ground,

On 2017-02-28 by (mod) pump kicks on and raises pressure gage to 70 psi in 10 seconds.

Turn off water into the home.
If pressure falls then the problem is typically a bad foot valve in the well, a bad check valve at the pump, or a leak in well piping.

On 2017-02-28 10 by Sanna

With no water running in house, the pump kicks on and raises pressure from 40 psi to 70 psi in 10 seconds. pump turns off. pressure gage shows pressure falls to 40 psi over 4 minutes. pump kicks on and raises pressure gage to 70 psi in 10 seconds. and repeat

I am hearing water running into what sounds like a fairly empty pressure tank.
how do I know if the problem is the pressure tank or the check valve??

On 2017-02-26 by erika

see above. Motor shuts off need toreboot

On 2016-12-10 by (mod) tank will lose pressure after 10 psi

Anon:
Sounds like a leak at the tank or piping or else water is running somewhere OR a check valve is not working.

On 2016-12-10 by Anonymous

My pressure tank will lose pressure after 10 psi

On 2016-08-14 by (mod) What would cause the pressure switch not to close when the power is turned on?

Anon

Pressure in the system above the CUT-IN pressure setting

NO voltage to the switch itself - a loose or open wire

Switch including a pump protection feature that needs to be manually turned back on.

Clogged pressure sensing port on the switch

Search InspectApedia.com for WATER PUMP WON'T RUN to read diagnostic and repair details.

On 2016-08-14 by Anonymous

What would cause the pressure switch not to close when the power is turned on?

On 2016-05-30 by (mod) - If I run a hose full throttle, after 3 minutes the flow will almost come to a halt.

John:

Check the flow rate in your well. Or search InspectApedia.com for DIAGNOSE POOR WATER PRESSURE to read details.

On 2016-05-30 by John

I have a deep well pump, 110'. The outdoor spigot is the first branch coming off the main line after the tank.

If I run a hose full throttle, after 3 minutes the flow will almost come to a halt. The pressure in the tank is set to 42. The switch is set to 40/60. Water pressure in the house is marginal at any time. Any thoughts?

On 2016-03-19 by (mod) well pressure gauge drops and pump kicks on when water is off.

Glenn

If you are sure no water is being run in the buiding I'd look for a leaky foot valve or a leak in well piping.

See WATER PUMP INTERMITTENT CYCLING

On 2016-03-14 by Glenn

well pressure gauge drops and pump kicks on when water is off. Toilets are off no lines running

On 2016-03-09 by (mod) pump cuts on and off when water to the house is turned on

Stan that sounds as if you have either a plumbing supply pipe leak or a running faucet or toilet in the building.

Also check for a water-logged pressure tank if your pump is cycling on and off rapidly.

On 2016-03-09 by stan

my house pump cuts on an off/ i/ve drained the tank an filled it back up/

as long as i keep water to house cut off the tank stays presurized/

as soon as i open to house th presure drops back down then it runs back up/ i haved check every thing what could be wrohh

On 2016-02-21 by (mod) Is there any sort of pressure switch failure that can cause a loss of pressure?

Walker

In my opinion pressure switches are on-off devices. They do not cause a slow loss of water system pressure between on-cycles of the pump. Rather there is a leak somewhere, either on the usage side of the pump and tank, or on the pump and well side.

Shut off all output water to your hydrants. If pressure drops there's probably a bad foot valve or a leak in well piping, or on occasion, a leak in the pump body itself.

On 2016-02-21 by Walker

I have a shallow well supplying water to 3 hydrants and an automatic waterer. Old Goulds jet pump with pressure tank, standard setup. The system has a slow loss of pressure which causes the pump to run every 1.5-2 hr whether water is running or not.

One of the hydrants and waterer were just added this summer but I have a shutoff for that line and I'm certain there isn't a leak there. The other two hydrants run off the same line leaving the pit and I think I either have a leak somewhere on that side OR a faulty pressure switch.

My question is: Is there any sort of pressure switch failure that can cause a loss of pressure? The hydrant lines have been there for years but seem to be in good shape, hard to believe a leak would have suddenly developed.

On 2016-01-29 by Terry Greco

If a toilet is running in the house will that cause the well pump to over heat and just down? The pump was replaced about 3 years ago and one day last summer we had no water. I called a well repair man and he changed the gauge and just the pump down for 30 minutes and then it worked.

It just happened again today and I shut the pump down for 30 minutes and now it is working again but why is this happening. It is a submersible pump.

On 2015-10-29 by water then no or just drips

Our water has started either having none when we turn on faucet to slow drips... then after a bit it will work just fine then a few days later same thing...no water for a little then it will slowly start... help!

Question: why would my submersible pump system recovery time have gotten so much longer?

I have a well with a pump at 60'. Recently the pump "recovery" time has increased dramatically. When I check the ohms on the electric it appears that there is no problem and when checking amps when running, it is drawing about 10 amps. What can the problem be? - C H Werner

Reply: some causes of dropping water delivery rate from the well

C H

In addition to the diagnostic articles listed earlier in the article above, you should check out our two approaches to diagnosing loss of water pressure
: WATER PRESSURE LOSS DIAGNOSIS & REPAIR and

in table form, WATER PRESSURE PROBLEM DIAGNOSIS TABLE.

If your well pump is running longer to reach the pressure control switch cut-off point, I can suggest several causes (listed in the above article and table) that you will want to investigate:

- the water level in the well may be dropping or the well recovery rate is deteriorating; when the well pump is protected against running dry by a tailpiece or other equipment then the pump may simply run longer to satisfy the pressure tank and control.

See WELL FLOW TEST PROCEDURE

- the well pump impeller assembly could be damaged

- the well pipe foot valve or pickup strainer may be clogged -
see FOOT VALVES, WELL PIPING

- the voltage may be improper or a bad electrical connection may be delivering low voltage to the pump. You'd think the pump wouldn't run at all but that's not always the case.

- there could be a leak in the well piping anywhere between the building water tank and the water pickup in well bottom

- water could be running in the building at the same time that the pump is running - perhaps one or more running toilets that were not notices

- something else that we haven't thought-of

Keep us posted on which of these you find - it will assist other readers.

Question: water pressure falls to zero and pump doesn't come on

(Oct 31, 2011) joe schuler said:

we are experiencing problems with our water system that feeds two homes. Initially we experienced low pressure and no water in both homes.

The repairer adjusted the pressure switch this seemed to work for a short time then the water tank ruptured (we think unrelated to pressure switch as it was an old iron valve fitting on the tank bottom that broke.) Then we replaced the tank and pressure switch.

The problem again appeared to be resolved but by morning we had no water . Then we thought it must be the pump so we replaced the well pump. we again thought that would work but it didn't. Sometimes the pressure will drop to zero and won't come on. Other times it will come on when it reaches 30 psi.

It will shut off at 50 psi then it will slowly bleed down and may or may not kick in at 30 psi. Any suggestions will be appeciated. Thank you.

Reply:

Joe, your question about lost water pressure was of course critical for the occupants of the two homes, and I suspect a debris-clogged pressure gauge - see

With no other information about your system you will also want to see our WATER PRESSURE PROBLEM DIAGNOSIS TABLE or at the home page for this topic WATER PRESSURE LOSS DIAGNOSIS & REPAIR - home

Question: water runs out and does not come on until I tap the switch

(Jan 26, 2012) Rory said:
Water turns off and have to wait for it to turn back on, sometimes have to go tap the switch to get to work i see adjustment screws which one is for what? I put a larger water tank on I guess I need to adjust something?

Reply:

Rory: if tapping the pressure switch turns the pump back on it could be a bad switch, burned contacts, or a clogged pressure sensor at the switc

Question: short draw down cycle before pump comes on

(May 26, 2012) bwaters said:
our water pressure is good for about 60 seconds ,then falls low , we already changed the pressure gauge,but didn't help

Reply:

B Waters

Sounds like you have what I call a short draw-down cycle after which you're running on pump delivery pressure alone, and perhaps a pump that is not powerful enough to get ahead of the rate you are running water. If that's the case you may have a waterlogged pressure tank.

Question: pump keeps running, pressure never goes above 40

(Nov 16, 2012) Kevin said:
I have a well 120 ft deep, 90 ft to hit water. the pump runs constantly but does not give more then 40 psi

Reply:


Kevin:

When a pump runs continuously but never gets above 40 psi there could be several possible explanations such as low water in the well, well piping leaks, damaged pump or impeller or bad voltage, even a bad gauge or pressure control switch or switch sensor.

At the start of this article click to Show Related Topics

then click on WATER PUMP WONT STOP RUNNING for complete diagnostics.

Question: can't get the well pipe out

(Jan 23, 2014) Ilene said:
The pipe that goes in the ground to the water will not come up to change the foot valve. Any suggestions?

Reply:

Ilene, if the well pipe is jammed in the well, a problem that can occur for several reasons, well drillers and plumbers who work on wells have special devices and equipment to free up the piping and pull it from the well.

If you search InspectApedia for

Well Pipe Grabbers & Fishing Tools for Retrieving Stuff you Dropped Into the Well

you can see our article about this equipment.

Question: pressure gauge was stuck, water comes out fast then just drizzles.

(Feb 16, 2014) John Summers said:

I have a well and pump. I just replaced the pressure gauge, it was stuck at 40 then would go to 60 psi when I turned on water in the house. The water would come out fast for 2 seconds then drizzle, but the gauge would still read 60 psi.

The new gauge says 60 psi when idle. I can turn on water and it has a nice decent flow, but when i open another faucet it comes to little or no pressure. The gauge will also slowly drop but never go past 50 psi, so I can't see where the cut in comes on

. I put air in the tank to go to 38 psi. I didn't re-check it after i put on the new gauge. Also the pressure switch says its suppose to be at 30/50, but when it clicks off at 60 i assume thats because the previous home owner has it set to 40/60. I've been going through all these articles, but I can't seem to find where to start. Thanks in advance.

Reply:

John,
I'm not sure what's happening in your house, but in general if we have good water pressure (really we should be saying good flow rate) at one fixture but the flow slows to a poor rate when a second fixture is run, I suspect that the problem is not water pressure but water flow rate that is being limited by clogged piping.

If you click on the "Show or Hide Related Topics" link near the top of this page you'll see a list of related topics including

WATER PRESSURE DIAGNOSIS, PRIVATE WELL - home

that begins a series of diagnostics on poor water "pressure"

Keep us posted.

(Feb 16, 2014) Anonymous said:
Thanks. I'll check out those links. I also have a garden tub and if i turn that on, no water from any other fixture will turn on. I just re-checked everything. It kicked off at 40 just as i expected and it has 38psi in the tank. THanks again.

Reply:

Here's another clue: is hot water pressure different from cold?

(Feb 16, 2014) John Summers said:
no they are the same. I did notice that the garden tub has a really fast burst followed by a slow drizzle, where everything else has decent until another fixture or toilet comes on

(Feb 16, 2014) John Summers said:
I've also checked under the crawl space for any signs of leaking. I haven't found any sign yet. I've ran my hand up the pipe to where it leads into the house(I have a crawl space). I've visually checked the insulation, and felt it as well. No water spots, to drips, nothing. I've also taken the thing off the garden tub faucet to see if it was dirty or clogged and there wasn't anything on that either.

Oh yeah also all pipes are PVC. I'm not sure if that helps or not. Before this issue happened, I could run both showers and the garden tub with really good pressure

Reply:

OK John, so it could be something else but the system is acting as if there were small diameter piping or a clog; typically that shows up as water pressure almost instantly falling off when a fixture is opened.

(Feb 16, 2014) John Summers said:
I was reading that you guys recommened 3/4 piping and mine is 1/2. I also read that you guys said it doesn't just go bad. There is a filter of some sorts out there, maybe that could be a suspect. I don't really know very much about plumbing except what I've read on here.

Reply:

John,

Hot water pressure (flow rate) = cold water pressure argues against a mineral clog problem since hot pipes clog first

Poor water pressure at ALL fixtures argues for a system problem or a clog or partly closed valve or dirty water filter at or close to the building water supply system;

Often clogged sink strainers are at fault but if water pressure (flow) is poor at a bath tub (that does not use a strainer) that argues for a system problem.

Plastic water pipes are more resistant to mineral clogging than copper or galvanized iron.

If there is a water filter that's where you should start: put it on bypass or remove the filter from the canister and re-check the pressure.

(Feb 20, 2014) John Summers said:

hanks for your help. I felt like an love. This is my first home, so I was unaware that the filters should be changed monthly

. I changed it and now its working even better before. THanks to your articles, I found out troubleshooting the water pressure tank that the psi was 10 below what it was suppose to be. And now i know to change the water filters more often. Thanks again for your help.

Question: intermittent low well water pressure

(Mar 5, 2014) dave said:
water pressure in my well water is low then intermittently returns to normal

Reply:

Dave, we have a diagnostic article for your question. Near the top of this page click on "Show or Hide Related Topics" to see the article list then choose

WATER PRESSURE INTERMITTENT (comes & goes)

If that article leaves you with questions don't hesitate to ask

Question: the pump cuts out with a steady quick drop on the pressure gauge back to 0.

(Apr 6, 2014) Roger Beauregard said:

I am installing a new well system in the country. My system seems to be short cycling. When I hit the manual electric switch, the pressure unit allows the pressure to build to 38 which is normal. Then the unit cuts out with a steady quick drop on the pressure gauge back to 0.

I hear water running back into the hoses. Initially there was a force of air before the water ran out, now there is no air but a nice steady water flow. But the system won't stay on, loses the pressure and water seems to be running back into the well.

Reply:

Roger

I guess I'd call this a quick pressure drop after well cuts out;

Either there is no pressure at all being built in the pressure tank or there is no working foot valve or some other big leak in well piping.

Keep me posted

Question: new house, sometimes we have no water

(Sept 25, 2014) Mark said:
We just bought a new house when we moved in we noticed that periodically we would be with outt water. The well tank would read zero and then randomly would fill again. We had a plumber come and look at it.

He replaced the tank as it was older, new pressure switch and new relay switch,pulled the pump out of the well visual inspection looked ok, lots of water in the well even when tank is empty.

However the problem remains. When running pump works great, fills tank quickly, even with high demand. But about every other day we will find ourselves with out water.

Reply:

Mark,

Please see WATER PRESSURE INTERMITTENT LOSS and let me know if that solves your problem.

Question: pump leaks, will this cause the pump to run?

(Sept 26, 2014) archie said:

Pump is leaking underneath will this make the pressure drop making the pump turn on every say 6 or 7 minutes?

Reply:

Yes, sure.

Question: My pump cycles on about every 12 to 15 minutes

5/17/2015 Jim.fouts said:

My pump cycles on about every 12 to 15 minutes. I.have isolated the house from the tank and pump and it still cycles. I.have isolated the tank from the house and pump and it does not appear to lose pressure. When I isolate the pump it drops to zero and cycles on and off in seconds. The foot valve and pump were replaced 15 years ago.

Reply:

Jim

Take a look at this diagnostic article for the problem you describe

WATER PUMP INTERMITTENT CYCLING

and let me know if questions remain.

...


Continue reading at WATER PRESSURE FALLS SLOWLY, ERRATIC PUMP - topic home, or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see WATER PRESSURE FALLS BRIEFLY THEN STOPS - pressure drops then stops dropping after pump turns off

Or see BOYLE's LAW where we explain P1V1 = P2V2

Or see WATER PRESSURE INTERMITTENT LOSS

Or see WATER PRESSURE COMES & GOES

Or see these common sources of slow dropping in water pressure and loss of well prime:

WELL PIPING CHECK VALVES

WELL PIPING FOOT VALVES

Suggested citation for this web page

WATER PRESSURE FALLS SLOWLY FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER SUPPLY, PUMPS TANKS WELLS

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