Speaking of water I noticed a lot of folks, at the Flea Market I have a store in, are buying old Camel Baks.
If I was not there to see what the original owner put in them Camel Baks I would be careful about them. Diarrhea is rough on the road march.
The other advantage of the canteen is you can use one to purify as you walk and the other to drink. Then at the next water point switch and walk.