RO units can also suffer from poor handling and use. Improper storage, failure to clean and exposure to various chemicals can make these units unreliable. Most RO membranes suffer if they are exposed to petroleum products. Clue: if the Navy doesn't want them any more they may be cost-prohibitive to repair. Maybe not.

For survival use I would hate to be putting my trust into a RO unit only to find out the membrane or seals are pretty much shot. IMHO it is better to know you Don't have something than to think and act like you do and then find out you really don't. Knowing I didn't have a functional RO unit I could ration my water much more closely, set up a coupe of solar stills or allocate more time to finding water.

Thinking I had a functioning RO unit I might neglect those options because I'm firm in my belief that water was just a few squeezes away. Now, hot tired and thirsty I break out my RO unit and are sorely disappointed. Now I'm both dehydrated and my is sinking fast because I have fooled myself.

I don't know abut these particular models but last I heard Katydyn offered replacement membranes and seal kits for all its products. IMO it would be wise to replace the membrane and seals if they are anything less than pristine.