Water ATMs operate as cashless vending machines for water. A customer uses a smart card, which can be recharged, to draw water from the kiosk.The proposal in this regard was first made by Sarvajal, a social enterprise established by the Ajay G Piramal Foundation.

A customer can draw up to 20 liters of water at once or less, depending on his need. Money is automatically deducted from the smart card, depending on the volume of water drawn from the ATM at affordable price.