I've been told that Codsworth purifies water if he's just wandering around a settlement. If this is accurate, where do I collect it?

no its not like fallout 3, what you do is you need to break down some materials and build a water purifier in sanctuary, you place the purifier in the water near the houses and put a generator close to the purifier and then run a wire which isn't too difficult then the water will go to the workshop, the spot where you spawn when you fast travel to sanctuary

When I talk to him, he gives me a bottle of purified water. Not sure how long it takes for him to get another one... less than a week for sure.

alizarin327: he does give you purified water once in a while!

oh ok well i never talk to him but build a purifier and you'll get like 40 bottles of water every couple days

Excellent. Thank you both.