Why does my toilet make a low-pitched moaning noise when it refills?

Question

This hasn't happened before, but now it's making a low-pitched moaning noise (like a low-pitched vuvuzela) every time we flush the toilet.

This happened only very recently, and we also just recently replaced the fill valve. The replaced fill valve was extremely quiet, so this noise is just very sudden.

Also, if I push the water hose from the toilet to the water line a little bit, the noise disappears immediately.

Answer 1

This happened to me once. I solved it by shutting off the water all the way and turning it back on again.

If that doesn't help, try taking the parts out one by one and flushing them with water. It's possible a small piece of debris (Such as an iron or mineral deposit) got stuck in there.