the obvious answer to this is surely reduce consumption - why have they set 100 liters a day as a minimum - back in the 1800s people coped with around 16 litres - truth is just like power use we have allowed ourselves to get more and more wasteful of resources - simple things can be done to reduce water use - shower not bath, only use washing machines and dish washers when there full or wash small amounts of dishes by hand - water your plants with a can not a hosepipe - new tech will help somewhat to with things like machines already on the market that can wash clothes with just a cup of water