A stack of plastic containers sits under a rock ledge beside the trail, covered with a faded tarp. Water cache - someone set this up as a resupply point. The tarp has been undisturbed for a while. Dust has settled in the creases.
Three of the four containers are empty. The fourth is full, its cap sealed with wax.
Choices
1
Take the water. A cache this neglected isn't being maintained. Finders, keepers.
no requirement
Success
The water looks clean and smells fine. You break the wax seal, taste it - good. You fill your containers and leave the empty ones stacked neatly. Whoever cached this would probably rather it be used than evaporate.
Failure
The water looks fine but when you open the seal, a sharp chemical smell hits you. Something has leached into it from the container - the plastic has degraded in the heat. The water is toxic. You pour it out and re-stack the empties as a warning.
2
Leave it alone. Someone cached this for a reason, and that reason might still be walking the trail.
no requirement
Success
You note the location and leave everything as you found it. If the cache owner is still active, taking their water supply is a good way to make an enemy you never see coming.
Failure
3
The container type, tarp material, and wax seal method tell you who set this up and when.
Pre-war HDPE containers - military surplus, rated for long-term storage. The tarp is treated canvas, not synthetic - handmade, probably settlement-produced. The wax seal is beeswax mixed with pine resin, a preservation technique used by a few specific communities. This cache was set up by someone who knew what they were doing, probably as part of a trade route supply chain that dried up. The water has been properly sealed and stored. You take it with confidence and leave a cap under a rock as payment. Good practice.
Failure
You identify the containers as military surplus, but the tarp and wax seal could come from half a dozen communities. Your analysis narrows the origin to 'someone competent,' which you already knew. The water is probably fine, but 'probably' is a word that kills people in the desert. You take a small amount and move on.