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We are at the end of a fairly large extension project which included the installation of a new water main. This is a largish old property which is supplied in different parts by two branches of rising main both of which are supplied by a common supply meter. The new extension is fed by one of the branches.
Early in 2020 (before the new extension was in use) I began to notice a low rumbling or throbbing noise intermittently and only after midnight - 1.00a.m. I could hear this in the bathroom of the older part of the property. It took me quite a while to track it down. At first I thought it sounded like a mains hum and since the main distribution board was adjacent to the bathroom it seemed plausible.
Later on (after a few weeks of head scratching after dark) I heard the noise in the kitchen of the new extension. It was fairly easy to trace it to the new water main (32mm HDPE) where it came up through the floor. Not only was it clearly audible I could feel the pipe vibrating. The sound level was quite high - certainly enough to disturb sleep. This would be a problem since the supply also fed a new en suite adjacent to our new bedroom.
I can't actually be sure that the start of the noise coincides with the new extension works, but its is a reasonable assumption I believe. However it should be noted that the noise can be heard in both branches of the water supply.
The sound itself does not relate to any opening or closing of valves, taps or other flow controls. It simply starts spontaneously. This can be at any time after midnight, typically 02:00 - 06:00, sometimes for hours on end. The sound will start and stop intermittently, typically a minute or two on then a similar period off. Some nights there is no noise at all - probably 50% of the time.
I have had an inspector from the local water supplier attend a number of times - they have been very good but have not yet listened to any of the recordings I have made of the noise, and I have quite a few now. What he did do was change a non-return valve in the water meter from a spring loaded type to passive return type. This did not stop the noise recurring. It did however change the character of the noise - more like a two stroke on tick-over now.
I have monitored the incoming water pressure for clues. During the day the pressure is typically around 3 bar rising in the evening towards 4 & 5 bar. Something I have observed and which I find really odd is that typically late in the day the pressure will rise to 5 bar and above and then the pressure gauge needle will begin to oscillate wildly. The pressure will drop back after a variable amount of time only for the sequence to repeat. I have videos of this behaviour, but again they have not been viewed.
I am pretty sure that this is not 'conventional' water hammer since it starts by itself and typically in the small hours when no one is using any water and there are no appliances in use. I don't have any problem with fitting a pressure regulator on the incoming main but I'm not convinced it will solve the problem. My gut feeling is that there is some sort of pressure fluctuation being transmitted from the main which is possibly setting up some sort or resonance. There's a large dose of speculation attached to this for sure, and if anybody has any insight, experience or indeed knowledge they'd like to share I would be most grateful.
Early in 2020 (before the new extension was in use) I began to notice a low rumbling or throbbing noise intermittently and only after midnight - 1.00a.m. I could hear this in the bathroom of the older part of the property. It took me quite a while to track it down. At first I thought it sounded like a mains hum and since the main distribution board was adjacent to the bathroom it seemed plausible.
Later on (after a few weeks of head scratching after dark) I heard the noise in the kitchen of the new extension. It was fairly easy to trace it to the new water main (32mm HDPE) where it came up through the floor. Not only was it clearly audible I could feel the pipe vibrating. The sound level was quite high - certainly enough to disturb sleep. This would be a problem since the supply also fed a new en suite adjacent to our new bedroom.
I can't actually be sure that the start of the noise coincides with the new extension works, but its is a reasonable assumption I believe. However it should be noted that the noise can be heard in both branches of the water supply.
The sound itself does not relate to any opening or closing of valves, taps or other flow controls. It simply starts spontaneously. This can be at any time after midnight, typically 02:00 - 06:00, sometimes for hours on end. The sound will start and stop intermittently, typically a minute or two on then a similar period off. Some nights there is no noise at all - probably 50% of the time.
I have had an inspector from the local water supplier attend a number of times - they have been very good but have not yet listened to any of the recordings I have made of the noise, and I have quite a few now. What he did do was change a non-return valve in the water meter from a spring loaded type to passive return type. This did not stop the noise recurring. It did however change the character of the noise - more like a two stroke on tick-over now.
I have monitored the incoming water pressure for clues. During the day the pressure is typically around 3 bar rising in the evening towards 4 & 5 bar. Something I have observed and which I find really odd is that typically late in the day the pressure will rise to 5 bar and above and then the pressure gauge needle will begin to oscillate wildly. The pressure will drop back after a variable amount of time only for the sequence to repeat. I have videos of this behaviour, but again they have not been viewed.
I am pretty sure that this is not 'conventional' water hammer since it starts by itself and typically in the small hours when no one is using any water and there are no appliances in use. I don't have any problem with fitting a pressure regulator on the incoming main but I'm not convinced it will solve the problem. My gut feeling is that there is some sort of pressure fluctuation being transmitted from the main which is possibly setting up some sort or resonance. There's a large dose of speculation attached to this for sure, and if anybody has any insight, experience or indeed knowledge they'd like to share I would be most grateful.
