I'm grateful to Derby Tup and Stolly for this as I really exist on tea and only use water in my camelback and sports drink on my bike, so far so good and I have raced a few deserts and had no issues. My worry is that whilst I would love to drink from becks and streams, agro pollution is a concern and so I carry drinks (and a 1st aid kit, torch, compass, map, TP and money for the phone - its a work thing!)

Who does drink from streams and how do you tell whats good?