Remember that plants need water to survive too. Where there are plants, there is water of some form.  

Place the container on hot embers, or preferably hanging it over a fire so the flames are just “licking” the bottom of the container. Even if the water looks pure, it can house health hazards. Boiling water kills off harmful bacteria and other microscopic organisms that may be looking to cause you to have illness. Alternatively, water purification tablets or filters can be used to remove pathogens. In order to cleanse stagnant and sludgy water, chemical purifiers or a solar still should be used to remove solid pathogens. Some water should not be considered fit for drinking under any circumstances. Examples of this water include swamp water or water that has deceased animals in or around it.

Never drink the fluid inside of a cactus. This can dehydrate you more and cause adverse effects. Never drink the fluid or stored water from any unidentified plant, as this can lead to illness or death.