Normally when backpacking I used to tend to just boil the water if if the water looked a bit iffy or I didn't trust the source it came from, but that was all OK if it was for a making a brew or a meal but I found it was time consuming as then the water has to be left to cool if it was then used fill up a playpus. Finally there was then the issue of the amount fuel used to boil the water which sometimes is not so easy to replace when doing an LDP such as the pennine way. And so in the end I bought one of these,Travel Tap
The flow can be a bit slow and time consuming if you want to say fill a platypus etc, But after buying the travel tap I have done away with the platty and now I prefer to just drink straight from the bottle and have option filling up as I go,from any water source and also find it much more convenient rather than running out of water in the middle of nowhere and then not having a good water source for miles to top up the platty.
At 160 grams its not that much more weight than say carrying a sigg bottle aswell.