# Loud Banging When Well Pump Turns On



## porkfriedrice (Jul 17, 2011)

Hello there. Moved into my house almost four years ago, up until about two months ago everything had been fine. 

If the water in the house hasn't been turned on for awhile, when the well pump turns on it is accompanied by a pretty loud bang that can be heard upstairs. According to google the problem might be water hammer, but I'm not sure. I've also noticed that the sediment filter has been getting very dirty quickly, with some pretty noticeable white chunks in there. The piping from the well tank to where the old pipe comes out of the floor was replaced about two years ago due to corrosion, but like I said the noise has been a recent thing. Any idea what could be causing this noise? Even if it's something I can't fix myself, it would still be nice to know what I'm dealing with here.


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## SeniorSitizen (Sep 10, 2012)

When well problems arise the first thing I recommend is to do a draw down test. This tells us yes or no to any pressure tank problems.

In case you aren't familiar, measure into a container and record the number of gallons drawn between cut out pressure and cut in pressure of the pressure switch. The tank should have those gallons of draw down on the label.


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## joecaption (Nov 30, 2011)

Is there a pressure tank?
If so does the pump turn on as soon as a faucets opened, if so there's your problem.
It's low on air, or the bladder has burst and the whole tank needs to be replaced.


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## porkfriedrice (Jul 17, 2011)

SeniorSitizen said:


> When well problems arise the first thing I recommend is to do a draw down test. This tells us yes or no to any pressure tank problems.
> 
> In case you aren't familiar, measure into a container and record the number of gallons drawn between cut out pressure and cut in pressure of the pressure switch. The tank should have those gallons of draw down on the label.


I did as you said, and I was able to get almost five gallons between cut out and cut in. Unfortunately, the tank label is so corroded that I can't read it. 


joecaption said:


> Is there a pressure tank?
> If so does the pump turn on as soon as a faucets opened, if so there's your problem.
> It's low on air, or the bladder has burst and the whole tank needs to be replaced.


Yes there is a pressure tank (see pic). I don't think it's the problem, like I said I was able to get almost five gallons before the pump turned on again.

When I went downstairs to check the tank label after the draw down, there was a foot diameter wet spot on the concrete, below the spigot in my picture above. Not the one with the red on/off valve, the other one with no valve directly under the pressure gauge. Is that some sort of relief valve? I have never seen that much wetness there before, though in the past there have been very small drops in the same place.


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## joecaption (Nov 30, 2011)

Did you put a pressure gauge on the valve at the top of the tank?
Should be a few PSI below the pump max pressure.
Push on the valve stem and no water should come out.


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## porkfriedrice (Jul 17, 2011)

joecaption said:


> Did you put a pressure gauge on the valve at the top of the tank?
> Should be a few PSI below the pump max pressure.
> Push on the valve stem and no water should come out.


Yep, did this last weekend after reading up on it on here. Air pressure was low, so I put more in. No water from the valve stem either.


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## jogr (Jul 24, 2007)

The bang could simply be movement of the pipes. Check to make sure all your piping is securely fastened so that it cannot move.


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## porkfriedrice (Jul 17, 2011)

jogr said:


> The bang could simply be movement of the pipes. Check to make sure all your piping is securely fastened so that it cannot move.


Could be. Though my whole house is plumbed with PEX besides what you see in my pic and maybe six feet more total that leads to the sediment filter and then to the shut off valves for the rest of the house. I'll check it out though.


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## Ghostmaker (Mar 2, 2013)

Pex needs to be secured every 32 inches our it tends to flop around.


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## SeniorSitizen (Sep 10, 2012)

porkfriedrice said:


> When I went downstairs to check the tank label after the draw down, there was a foot diameter wet spot on the concrete, below the spigot in my picture above. Not the one with the red on/off valve, the other one with no valve directly under the pressure gauge. Is that some sort of relief valve? I have never seen that much wetness there before, though in the past there have been very small drops in the same place.


This is really pointing to the valve mentioned below the pressure gauge. Yes, that's a relief valve and it would be of value to know if it has a visible number concerning its relief pressure and that correlation to the pressure on the gauge when it pops off.


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## porkfriedrice (Jul 17, 2011)

In order to better pinpoint where the noise is coming from, I listened/observed while the water was running and waited for the pump to kick on. 










The noise seemed to be coming from the area circled in red. There was no movement of the pipes that I could see.



SeniorSitizen said:


> This is really pointing to the valve mentioned below the pressure gauge. Yes, that's a relief valve and it would be of value to know if it has a visible number concerning its relief pressure and that correlation to the pressure on the gauge when it pops off.


I looked for markings on the relief valve and there aren't any.


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## gassyplumber (Sep 17, 2014)

Drain down pressure tank and check air pressure. Could be water hammer from pump and toasted bladder in tank


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## porkfriedrice (Jul 17, 2011)

gassyplumber said:


> Drain down pressure tank and check air pressure. Could be water hammer from pump and toasted bladder in tank


I did this two weeks ago (see post #6), the tank was low on air so I filled it to the proper pressure. Also no water came out when I pressed the schrader valve. Any other way to tell if the bladder is shot?


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## SeniorSitizen (Sep 10, 2012)

Quote pork: I did as you said, and I was able to get almost five gallons between cut out and cut in. Unfortunately, the tank label is so corroded that I can't read it.
***************************************

Your draw down test of nearly 5 gallons for a residential system is about as good a test as there is with label or no label.


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## porkfriedrice (Jul 17, 2011)

Well, I guess I'll have to call in a pro to solve this mystery. Should I contact a plumber or a well company to check it out?


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## SeniorSitizen (Sep 10, 2012)

At 3:00 O'clock in the circle you have drawn it looks as if a new brass in-line check may have been installed. Hold it in your hand while the pump kicks on to determine if you can detect the noise there.


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## karin els (Oct 27, 2014)

Im going to take a shot that your check valve on the pump itself may be bad, and there may be a small air leak allowing the water to draw back down the pipe into the well. Then, when the pump kicks on after sitting for a while, you will get a hammer noise. If you were getting the hammer at the end of the cycle, id say your check valve at the tank is faulty, but if its when the pump kicks on, its prolly the one below.


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## porkfriedrice (Jul 17, 2011)

SeniorSitizen said:


> At 3:00 O'clock in the circle you have drawn it looks as if a new brass in-line check may have been installed. Hold it in your hand while the pump kicks on to determine if you can detect the noise there.


Had an opportunity when the pump hadn't run for awhile to try this. I couldn't feel any abnormal vibrations. 

But I did notice that when the pump went on (along with the noise), the pressure gauge dropped to almost 20 PSI for a moment and then shot back up as the pump continued to run. I don't think I've seen it do this during normal operation.


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## SeniorSitizen (Sep 10, 2012)

Next in attempting to solve the mystery is to attach a coffee filter covering the relief valve discharge. When you next hear the noise check the filter for moisture. It should be completely dry.


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## porkfriedrice (Jul 17, 2011)

SeniorSitizen said:


> Next in attempting to solve the mystery is to attach a coffee filter covering the relief valve discharge. When you next hear the noise check the filter for moisture. It should be completely dry.


Did this a little while ago. There wasn't any moisture. But like I said in one of my previous posts, I did see quite a wet spot under the relief valve a few weeks ago, and even before that I would sometimes notice that it was damp. This was even before the present noise issue.


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## porkfriedrice (Jul 17, 2011)

Hey there, back after a year. I stopped replying to this thread since the noise went away on its own. Now almost exactly a year later, it's back, same symptoms, though now it seems that there is more water being released from the relief valve (see post #4). Any ideas why this is happening at practically the same time of year? I live in the northeast and there has been a lack of rain this year, not sure if low water level in the well has anything to do with it. Don't remember if we had the same drought conditions in 2014. Anyway, probably going to end up having to call a well guy.


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## KC_Jones (Dec 1, 2014)

I agree with post #17 bad check valve on the submersible pump. Grew up on a well, in a neighborhood with wells, pulled more wells than I care to count. The noise you describe is exactly what happens when that check valve goes bad, it's loud. Bangs that relief and can make it pop open from the "violence". Ours would wake the house up at night if someone flushed a toilet causing the pump to come on. If you can't pull it yourself call in someone to do it. I would also recommend checking condition of ever thing while it's out, wiring piping etc. Pulling a well isn't something you want to do too many times. And there was that day that my father didn't listen and we had to pull it twice in one day, I will never let him forget that one.


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