Okay, I need advice: We moved into this 10-year-old house recently. When we first got our washing machine, we heard a low humming/buzzing/weed-eater type noise coming from the basement. It gets worse if we use our outside hose bibs, or if anyone dares to flush a toilet while the DW is running, etc.

We called the city to have them check the meter, since that's where we thought the vibrating hum was coming from. The meter's fine (they replaced it). The hum is still there.

We had a plumber come to change the pressure regulator, under home warranty. He did that. The noise is still there.

The plumber suggested we change the backflow regulator, located under the pressure regulator but above the water meter. It seems like we all could finally track the loudest hum to that part. The plumber said he can't guarantee that that will help, and that in 30 years, he's never heard of having to replace a backflow regulator (this on is Wilkins, model number 700 Dual Check).

Everyone hears the noise. I would feel better if someone would tell me this is not the craziest thing they've ever heard of. I'm prepared to pay someone to fix it, but I HATE when the experts say "this is the first time I've ever heard of this" and I hate to start throwing money after wild goose chases to fix it, but I guess I have to. He even suggested we learn to live with it, but for the money paid for this house... and the principle of it... I don't think a noise like that should be ignored. It's got to signal that someone isn't working right. Right?