Filing your tank with water
Water for fuel technologies center around the principle that hydrogen which is an inflammable gas can be extracted from water and then used to power cars. This technology has led to the manufacture of many kits by various companies which allow drivers to turn their cars into water engines. If you want to run your car on water, you will buy this kit and then fix in your car.
The effect is, you will no longer fill your tank with gasoline but rather with water. You will use the ordinary water we have in the home and not anything more. The water you put in the car will be converted to hydrogen to serve as fuel for the car.