It goes to the PA. It is closely monitored by Israel to ensure nothing goes to Hamas.
Infrastucture projects are administered by various aid agencies, not Hamas.
I won't deny that corruption may go on with money they collect through taxes on their own people. There is very little accountability from what I read, which is very little so I'm no authority.
What I am saying is that to equate $3 pills allegedly found by Israel on the bodies of "several" Hamas fighters with responsibility for the decades-old water and infrastructure crisis is.. a red herring.
It distracts attention from the real problem.
Captagon is becoming problem for the Middle East. I'm sure you would find it in the pockets of many Arabs and perhaps Israelis as well. Though their problem seems to be fentanyl.
Drugs are a scourge, no matter what side you are on.
You might be surprised to learn Gaza has an anti-narcotics force that monitors all shipments from Egypt and Israel. In February they seized 50,000 captagon pills that came in thru the Israeli crossing. They claim it is part of a deliberate attempt to weaken their society.
Two sides to every story.
https://www.google.com/amp/s/www.newarab.com/news/hamas-seizes-50000-captagon-pills-blaming-israel-source%3famp
https://www.google.com/amp/s/www.timesofisrael.com/now-worlds-no-1-opioid-consumer-per-capita-israel-faces-addiction-epidemic/amp/