Other possibilities include knocking dirt out of clothes using sound waves and even self-cleaning fabrics.

The second main way that these experts are tackling the water problem is by finding revolutionary new ways of cleaning water that is already stuffed full of pollutants.

These include new techniques involving chemical, electro-chemical and biological treatments.

One technology now being developed is a sophisticated membrane - an artificial skin - that effectively sucks the pollutants out of wastewater and makes it good enough to be used again.

The third main area of research is in local recycling of water - allowing factories and even homes to recycle much of their own waste water in a safe and cheap way.

Space - the final frontier

For example when someone has a shower the wastewater will be collected, cleaned and recycled - to be used by the next person.

In fact, based on advanced techniques used in space by astronauts, experts say that soon we will be recycling as much as ninety per cent of a home's water.