Son can drink up to 3l of water

Okay so i just wanted some advise to cut down his water intake a little, my son is 2 and a half and drinks so much water, its liturally bottle after bottle straight away when hes finished his other bottle and if i dont get it for him there and then he will have a full blown melt down, my son is autistic, ive tried hiding the bottles and distracting him with sonthing else but he just doesnt stop until he gets another bottle, it wouldnt bother me but its in the night too last night he was throwing a melt down until 2am for a water, so im not getting much sleep either as he will be awake regardless what time he goes to sleep at 6:30-7