Fog horn/groaning sound from pipes since irrigation put in

Until we has an irrigation system installed in September, we never had any disturbing sounds from our plumbing in the house we've lived in for 11 years. Since we put in the irrigation we get a periodic groaning sound from the pipes -- it sounds like a fog horn; loud and continuous (not pulsing) and lasting from a few seconds to 10 seconds.

At first I only heard the sound after running upstairs taps or toilets after the water had been off for a while (middle of night or first thing in the morning). But now it's getting more frequent, happening a few times each day and night, and it can happen even when there is no running water.

I have to suspect the installation of the irrigation has something to do with it as the sound first occurred after installation. To make the connection, the plumber made a t-connection to the main 3/4" copper line that run just below the joists in the basement; the connection is also less than a foot from a second connection to the main line that goes to an outdoor spigot --the spigot connection runs up from the mainline than turn 90 degrees towards an exterior wall while the connection to the irrigation runs straight from the main line, in the same plane, so to speak. The irrigation line itself is 1" wirsboro, about 30' that it appears well secure, that goes through an exterior wall and then up to a backflow detector before going down to the valves of the irrigation system.

I tried once to flush out what I thought might be air in the system but the sounds have persisted. The irrigation itself was shut down a couple of weeks ago (there's a shut off valve inside close to where the Wirsboro connects to the mainline) but the sound persists.

What may be wrong?

Any suggestions? Help?

Check your toilets, it could be that one is overflowing and refilling periodically, with a washer vibration causing the noise

muggles said:

Check your toilets, it could be that one is overflowing and refilling periodically, with a washer vibration causing the noise

Click to expand...

Thanks muggles. There is toilet that prior to the irrigation work would run for a long time after it was flushed - 30 minutes or so. But there was no noise in the pipes until after the irrigation was installed -- the noise began within a day of installation and has continued -- even after the irrigation was blown out and shut off for the winter. It sounds to my uneducated mind that something in the installation increased the stress on that toilet (and my plumbing in general) that caused the sudden onset of these loud sounds. (note also that the sound continued even when I turned off the water supply to the toilet for a day). I probably need to repair the toilet. But I also need to find out what about the irrigation is adding stress to the plumbing, because if I do nothing about that, I will have fixed the symptom (toilet) but not the cause, and that could lead to more trouble down the road. Your thoughts?

Any other suggestions?

It does sound like a vibration caused by a valve (usually toilet fill valve or loft tank valve). Do you have a cold water storage cistern in the loft? If so it might be this vibrating (hence can be filling tank even after use of water).

If so change washer (or just change complete valve as only cheap).

Goldspoon said:

It does sound like a vibration caused by a valve (usually toilet fill valve or loft tank valve). Do you have a cold water storage cistern in the loft? If so it might be this vibrating (hence can be filling tank even after use of water).

If so change washer (or just change complete valve as only cheap).

Click to expand...

Thanks Goldspoon. The toilet/cistern has a chain attached to a rubber stopper and that stopped does need to be replaces as it has lost its seal. That may fix the toilet -- but it seems to me the toilet is a symptom of bigger problem caused by the installation of the irrigation, since it was only after the installation that we began hearing the fog horn sounds. Any idea what role the irrigation may be playing? I don't want problems there causing problems elsewhere in the plumbing.

Not sure. Sometimes these things can be coincidental. Always, in my admittedly limited experience, this has turned out to be a fill valve.