Update 2
Things are getting worse,........serious problem here.
By last night, the pipes in the wall coming to her "washer box" started making the wall "buzz",..........also in her master bath by the shower, you can hear the pulsations for several feet.
Gauge reading last night was still about the same, but the pulsations were swinging from 60 to 80 psi. The needle is moving back and forth so fast it is a blur!
I stayed over there last night, and took off today to deal with the utility company. Just got home a few minutes ago from her place.
A PRV valve will not even correct this issue I don't believe.
I tried an experiment early this AM while waiting to be able to call the utility company.
Put on her largest zone on her sprinkler system to drop the main pressure as much as possible. It went down to around 42 psi while running, and the pulsation swings were still there, as well as the noise.
OK,...........on to the utility company!
I get a guy from the plant on the phone finally around 9AM. He tells me,......"oh, you have air in your lines, and we need to bleed the system.
I shut off the main, and open all the cold water faucets, showers, and tubs.
He says let sit for 10 minutes, and close them, and turn the water back on,........no change.
Says to do it again, but this time open both the cold, and hot sides,........she has mixing type Delta valves in the showers, so I set them at mid-point. Wait 10 minutes water back on, no change.
Now they send a guy out. He looks at the gauge, and installs another on the opposite side of the house. Tells me there is air in the lines again! At this point, I tell him I have never seen air in lines do anything like this. I have heard water hammer, and I have seen pressure swings, but I have never seen this before. I can tell he really hasn't either by his demeanor, but he is sticking to it. I tell him I will try whatever he wants,...........SO,.....we shut off the water again, and open everything including hose bibs this time. Wait 20 minutes, and shut down, and turn the water back on.
Same thing again,.......now the guy is scratching his head, and he admits he has never seen such a swing, nor at that rate of pulsation.
Next he gets on the radio, and then he tells me to turn on all 3 showers on cold,.........while he opens a fire hydrant about 400 feet down the street.
We do this for 15 minutes. Shut it down,..........SAME THING!
At this point he starts to tell me she needs to call a plumber, as he believes her "hammer arrestors" have gone bad!!!
I say BS,.......this is on your side, and furthermore how in the world did my mother fill her plumbing full of air, unless it came through their service lines.
I am a smartazz at times, and said that I had not hooked up an air compressor to her plumbing recently.
There is a home right next door, that is getting close to a CO, and their meter was put in a couple of weeks ago. I say lets toss a gauge on one of their hose bibs.
Guess what,.............same thing there!
Now he can't tell me that it is her "house."
To finish,........when I finally left to do a call,........there were three guys out there, and they were sending others out to blow off hydrants for quite a distance.
Also digging up both meters, and flushing their lines.
To give the guy credit,......after he saw it at the other house, he quit trying to pass the buck. He told me they would find the problem, and take care of it, and call me on my cell. I turned off the fridge feed, as that was the most annoying noisemaker of the bunch.
Here I sit awaiting a call! What a blast.
Sorry for the novel, but I thought it might be entertaining for some!