PEX plumbing noise

Hi all! I'm an old retired guy on a very limited income so I have to fix things myself. Anyway, we are living in a house with a PEX plumbing system here in southern California and recently every-time someone flushed the toilet, we could hear a faint 'knocking' or 'pulsing' or 'pumping' sound. We have been here over 9 years and never heard the sound until the last few months. In the last few days the sound has gotten 'louder', and it appears to be happening even when the washer machine goes on. I have read a few posts about air hammer even in a PEX system, and I know that somewhere there is a 'manifold' that distributes the water to all the faucets, sinks and toiltes, but I have not been able to locate it. I am thinking the Manifold is hidden somewhere in the attack it is easy to tell it is no-where in the garage. Don't see any obvious leaks anywhere but since the sound is louder and more pronounced now I hope it isn't getting worse? Can anyone offer any advice on what to check and/or look for? And what to do about it.

Thanks in advance to all who offer help and advice!

 

If you have a shutoff valve on the toilet you can sometimes eliminate the knock by turning the valve closed slightly, which slows the water speed down. Experimenting with that might give you some relief.

 

I agree with XSleeper. There is a valve somewhere in your system with a loose washer that is vibrating when the water is in use therefore echoing through the whole system..

 

Hopefully you have a shutoff valve in the water supply pipe entering your home. Following the pipe from the output side of the shutoff valve should lead you to the manifold for the pex lines. There should be an access cover over the manifold, especially if each lines has a shutoff valve at the manifold.Hope this helps.

 

Thanks, it does. There is actually 2 attics in our home so from what you said, I would guess the manifold is in the smaller, and very hard to get into attic. Uuuugggghhhh! Oh well, once I fond the manifold, what should I look for, and how do I fix it?

 

Water comes into houses from the GROUND. So I highly doubt there are any shutoffs in the attic. Course, it is California so who knows.

 

Good manifolds have a shutoff valve on every outgoing line so you don't have to shut off all water to house when there is a problem with one line. How old is the house and what is the distance from water supply pipe ( into house) to attic?

 

Many PEX installations use manifolds, but not all. If you haven't found it yet, you likely don't have one - and it's installed more traditionally with one main trunk with the fixtures branching off. Nothing wrong with this installation, just two different methods.

(And I agree with the loose washer cause of the knocking. Could be the toilet valve, washer valve, or even the main shutoff)

 

Posting this reply again since I don't see it yet. From what I can tell, the faint knocking, or pumping sound is coming from the attic. And the sound goes on for about a minute or so after flushing the toilets in either bathroom/front or back. It also makes the noise when the clothes washer is filling. So I think the problem is not related to a single fixture. I don't have a water pressure gauge but we sure don't have any more pressure than we have for the last 9+ years. It looks like a 3/4 inch pipe coming into the house from the street if that means anything. Unfortunately due to age and some health issues I can't get into the attic. However, I can ask my son to go up there when he comes over but I need to know what to tell him to look for.

 

Have you tried what XSleeper suggested?
Doesn't require going into the attic, and definitely worth a shot.

 

Thanks. We tried adjusting the water inlet pipe to the front toilet with no effect. Now, my son hasn't been over yet to go up in the attic yet but in the meantime I have noticed that we get the knocking/pumping sound whenever any toilet or shower in the house is used, along with whenever the clothes washer is used. So, because of the fact that any large use fixture causes the noise, I don't think the problem is related to a single pipe or pex line is causing the trouble. Of course maybe one pipe is causing the others to vibrate.** Oh, and I went outside to take out the trash and walked past the water inlet pipe to the house. I could hear the slight tapping/knocking/pumping sound by the inlet pipe? Does this give a better idea of what's going on?

 

Try finding your main shutoff valve, which should be inside, near the location of your exterior pipe... and turn it closed. Have someone flush a toilet or two, then open the main shutoff valve until you start to hear that knocking.... then see if turning the main shutoff valve slightly closed gives you any relief. As already mentioned, you likely need to have a plumber find and fix the loose washer(s). It could even be on the main valve. Its fairly normal for the meter on your main shutoff to have a tick-tick-tick when the water is running.