Dragons Den water Filter
 

I was watching a Dragon's Den rerun on Dave this afternoon.

They had a product aimed at carrying water to isolated communitys and after disaters etc.

I'm not sure if these are availble to buy for joe public but I thought there would definatley be a market for overland travellers?? But maybe 50l water is to heavy for a motorcycle??

Safe Water and Easy Transport: ROSS Emergency Filter and Carrier : TreeHugger

But still a fantastic product for use in the developing world

In Malawi you can buy a 100ml bottle of AquaGuard for less than $0.50 (usd) ... you can clean probably a thousand litres with that. I used it extensively, no bad taste or effects on me. Maybe in other parts of the world conditions are different, but I would recommend means of treating the water instead of carrying it. Even in Sudan it was easy to come by water.