We don’t really appreciate how much water we use, until we don’t have it to use anymore. Water is the keystone to all survival – we cannot live more than a couple days without it, we cannot raise crops or livestock without it, and we cannot keep clean and free of diseases without it. Like food, there are many initial sources for water, but storage is less practical and water can be gathered, cleaned, and retained throughout the year if you take the time to learn and prepare.
Super simple, it comes down from the sky and you keep it until you need it, right? Well, kinda. In some states it is technically illegal to collect and use rainwater, but in a SHTF situation, I’m sure law enforcement will have greater problems to deal with. For survival purposes, it is best to filter rainwater before drinking or washing with it. However, if you are using it for gardening or to maintain a fishing pond (aquaculture), it doesn’t really need filtering.
This is water that has been used for cleaning purposes (shower, laundry, dishes, etc.) but is not polluted. Grey water can be used to water the garden or be filtered to water livestock. Generally, unless you are in dire need, grey water should not be consumed by people. If you have to drink it, filter and boil it first.
Check out this article on the details and importance of Boiling Water.
Water from rivers, lakes, or streams. This is tricky because you never really know what got into the water upstream. Chemicals, pollutants, waste, and dead bodies can contaminate water and make it deadly to drink without extreme filtering. If wild water is your only option, distillation is the best way to make it safe. Distillation isn’t difficult, but it takes time and a reliable heat source as you are collecting the steam from boiling water.
On to the next survival basic: Shelter