Hamas dug up some water pipes beneath old abandoned Israeli settlements in Gaza for rockets…In the far past from a time Israelis controlled Gaza.
Extrapolating this event in the far past this to dismantling the actual water supply of Gaza to make rockets is a slight stretch to say the least. Especially since we have satalite images of it being destroyed by Israeli rockets
I have not seen Hamas damaging any water supply systems that are in use. Only Israel is doing that.
The old pipes you referred to, beneath the abandoned Israeli settlements, were not in use.