those weird hdb sounds/noise especially in early mornings

not those typical marbles running down your ceiling noise.

i want to ask if anyone else hears this particular kind of noise like a steel train slowly grinding to a halt or sometimes like a donkey heehawing from far away. at first i thought it’s like an electrical kind of sound like an old electric fan dying but it more and more feels like a water or piping issue.

but the funny thing is that i hear it daily around 5.30am to 6.30am and is ruining my sleep. i assume it also happens during daytime just not silent enough to hear it. but in the morning it’s really loud and i can even record it.

is this something i can report to town council? anyone has this issue before? i live in the lower levels and this certainly was not an issue before. i am guessing maybe something changed with the water pressure.