Yeah - I'm an absolute sucker for clear water when I'm thirsty!

I had a nice long drink from the river Avon last year. Spent the whole night being violently sick!

It cleared up the next day though.
I also drank from a river in Spain many years ago and was sick and had diarrhoea for about a week before having to check into hospital. They put me straight on a drip. I was living rough, so it could have been bin food, but I always wondered if it was bad river water.
Having said that I've drank from a hundred rivers, streams and all sorts, and been absolutely fine too!
I bought a Sawyer Mini Filter this year thanks to Phil (Midnighthound) and I will never drink untreated water again!
I'll also stay away from river water completely I think as it could have been chemicals that made me sick.