Far more important than food and arguably as important as shelter is water. You must have it or you will die, period. The guidelines say that a person can go 3 days without water. That is under ideal circumstances. I have lived desert and tropical climates and let me assure you, you will NOT last 3 days in either of those environments without water, you just go through it too fast. I always recommend that you have water with you whenever you go out, even in an urban environment I carry a bottle (I prefer stainless steel) of water with me. If headed outdoors I make sure I know where water sources are and are likely to be and I also try to carry at least one way to sanitize water if needed (hence the stainless steel preference).
- Carry water whenever possible. It is better to have and not need; than to need and not have.
- Know where water sources are in any area you are going to be in.
- If you are in an area that you don’t know where water sources are, familiarize yourself on how identify indicators of water sources and terrain features that increase the likelihood of finding water. (I will link a post here explaining how to recognize these indicators)
- Have a means to sanitize water with you at all times. I keep a stainless steel bottle and means to make a fire so that can boil water if necessary. There are also chemical treatments and filters/ purifiers. Whatever works for you. Water can also be sanitized with UV rays from the sun or you can build a water filter from scratch, These are last resorts for me.
- Have a means to carry water if you find it. This can be as simple as a ziplock bag in your pocket, your water bottle or even a condom (unlubricated of course).