Water hammer...I think??

Hi all,

I am new here and need some help. Recently within the last couple of weeks when I flush the toilet in the master bathroom while I have the sink faucet on I get a high pitched noise coming from the toilet while it is filling up the bowl. If I shut the faucet off the noise stops.

Also, recently, whenever you flush the toilet in the downstairs bathroom while the bowl is filling up you get the same noise whether the faucet is on or not.

What is this and how do I fix it. I was thinking about replacing the fill valves in both but this is sort of weird why this would happen to 2 toilets at the same time.

Thanks for any help you can offer.

Glenn

Do you have a water softener? If so, that could be the case, but if not, it might just be your plumbing or water supply.

First make sure that the wall shutoff is opened all the way. It could be a loose washer in the shutoff.
If that doesn't do it, then I would look next to the fill valve.