As I mentioned in another thread, made PSK’s for brothers at Xmas; included Micropur MP1 tablets for water purification. Needed some sort of water container, but discounted condoms (too puncture-prone for my liking, and no practical way to repair, e.g. with tape, given their expansion/contraction characteristics).

Was in Costco one day, buying Tri-Tip (familiar to Californians); bagged the meat with one of the clear plastic bags commonly found in supermarket produce/meat sections. Noticed that their plastic bag was the toughest (thickness, tensile strength) I’d run across – significantly better than, for example, Safeway’s.

So I grabbed a couple, and used those for PSK water bags. They’re 19-in. x 13-in. Using a waterproof permanent felt-tip, marked 1-quart and 2-quart increments on each bag.

They folded nicely and, of course, weighed nothing. They’re larger than needed, since a bag full of water would be prohibitively heavy, but didn’t trim, figuring the excess would aid in tying-off after filling with a couple of quarts of water.

Yes, they can still be punctured, but in a pinch, repairable with duct or other tape. Because I’d included a collapsible 10-oz. cup/cooking container made from extra heavy duty aluminum foil in each kit (cut/fashioned from Reynolds Foil Hot Bags), I also included 6-in. of aluminum tape for possible cup repairs. Found this tape works equally well on the plastic bags. If you’ve ever used it, you know how sticky it is.