"One thing I started doing to “reduce” consumption, is to use a small amount of water for wudhu. Did you know that RasoolAllah Sallallahu Alayhi Wassalam used to use less then a 355 mL popcan worth of water for wudhu? (an Imam told me) Subhanullah!!! There are muslims out there who use atleast a gallon easy.
It’s pretty easy, just use your hand as an individual cup, (squeeze your fingers tightly) and the opposite hand to quickly turn off, and on, the tap, saving LOTS of water. This way the water isn’t running all the time even when it isn’t being used. I managed to only use half of a water bottle, which is about 250mL."
Source: Mujahideen Ryder