On a serious note, I have a piece of information and lesson learned............
I have a large "bag" style water filter like Capt. Nat's. For some reason on the trip it was leaking. This was pretty frustrating in a "survival" consideration since the unfiltered water was streaming down through the threads and dribbling along with the filtered.
I was unable to make a good fix in the field, but it almost seemed that the O-ring was a micro fraction too small. Now I have used it multiple times and it worked fine, so I was a little stumped.
My fix was to take plumbers tape and wrap the filter before putting the O-ring on it. This made the O-ring fit just a little tighter, and seems to have fixed it well.
I carry a small pouch of water line, cleaning sponge etc, that goes with the water filter. Now, included in this is a roll of plumbers tape. This will also be important in case the O-ring is lost or damaged during cleaning.....