We need help with the humming and vibration in our plumbing. Our house is a two-story house that is about 15 years old. Last March we began hearing a vibration when we would shut off an upstairs shower or when the basement washing machine shut off. This summer the noise became unbearable when the sprinkler system was turned on. I called a plumber who said we had a bad PRV and that we needed to move the sprinkler system intake above the PRV. He did the work and we still have the problem. When he left he set our water pressure at 70. After talking to another plumber he suggested reducing the water pressure to 40. We did this and the humming and vibration is quieter and shorter in time, but still there. We tried to think back at what had changed in our house. We did have to install a new toilet ball **** because it began the run all the time. We got some die tablets from the hardware store and placed them in all the bathroom tanks to see which one might be draining. It was the one we replaced. We shut off the water to that toilet until we are able to make it to a hardware store. The sound is still there. What else can we do? This is a very annoying problem.