Noises when drawing cold water

Good day!

After more than 20 years, I am now increasingly hearing a short, deep noise when cold water is drawn somewhere in the house. For example, when the washing machine starts working, when the toilet is flushed and the cistern refills, or simply when a tap is quickly turned on.

At first, I suspected everything where the water flows through the basement, such as the network operator’s taps, at least one of which is equipped with a spring, and for example also the backwash filter, which also has a spring inside. It must be something that can start to vibrate. If I heard and felt it correctly, the noise does not come from a specific spot but diffusely from a section of pipe. Such vibrations tend to spread through the house and then seem much stronger and louder far away than directly at the place of origin.

Now I am wondering: Is it possible that a limescale build-up has formed somewhere in the pipe system that clogs the pipe to the extent that a vibration forms when the flow starts? I mean: here in Berlin, everything calcifies if not regularly descaled, so why should it be different in a fresh water pipe system?

Assuming this is the case: How could something like that be eliminated? If something is vibrating somewhere, the next step would eventually be something breaking. And under no circumstances do I want a burst pressure water pipe in my basement, even though such a failure would quickly be noticed by sensors.

There is a drain screw in the house connection room with which I could empty the system. After closing the valve again, acid could be introduced somewhere at an angle valve on the cold water side above. I once remembered "warm descaling with acetic acid, cold descaling with citric acid." If a corresponding solution is left in the system for a few hours, thin residue should actually come out at the drain valve below afterwards, shouldn’t it?

Or are my considerations going in a completely wrong direction?

Matthias

It is probably due to the water pressure in your system. Presumably, the pressure is too high. Normally, you have a pressure filter after the water meter. You can adjust the water pressure there. However, there are also regular pressure reducers. Perhaps an old water pipe near your house connection was replaced or other components, so that the pressure of your water supply has now increased. That would be the first place to start.

The waterworks press the water into the network at about 8 bar. At my backwash filter, about 4.5 bar are indicated, and there were no significant changes there either. Are 4.5 bar already too much? I mean, this effect didn’t used to happen before...

Matthias

I have been inching closer to the scene of the event for days now. Apparently, I have now quite precisely pinpointed where the noise is coming from. But that does not necessarily mean that it is generated there. Pipe systems are capable of transmitting vibrations to completely different locations. Here is a recording from this morning. The recording was made at the moment water was drawn by a toilet flush tank two floors above. The microphone was in the heating cellar, where the fresh water pipe leads off with a branch. There, you can feel a clear mechanical vibration on the cold water pipe, which also has several 90-degree bends.

My suspicion: Over the years, this pipe section leading to the heating system has become increasingly clogged with limescale, so that there is a bottleneck somewhere. If cold water is drawn somewhere in the house, a vacuum is created in this branch, and the bottleneck in the pipe acts like a reed of a musical instrument.

But how do you fix the problem? You would have to manage to introduce an acid into the system that then dissolves the limescale.

Matthias

The problem is: when something starts vibrating, something usually breaks at some point. And a lot of water in the basement is one of the things I can least afford.

Matthias

That sounds like cavitation. Maybe first consult a plumber. And consider a water softener.