The survival rule of thumb is that you can survive 3 hours without shelter, 3 days without water, and 3 weeks without food.
While shelter is often taken care of except in wilderness survival situations, fresh drinking water can be a serious concern. Most people advise to have 2 gallons per day per person, but half of that is probably the minimum. There are numerous options to prepare to have pure water in your emergency survival plan.
Short term – The most common source of short term drinking water is bottled water. It is easy, convenient, and reliable. By buying a few cases of bottled water, 2.5 gallon jugs, or ideally, burying 35 or 55 gallon drums of water, you can ensure you have a week or two supply.
Middle term – After bottled water supplies run out, you can start filtering water using a common hiking water filter. Water can be taken from pools, ponds, rivers and lakes if you have containers to carry it in. This is will until the life of your filters has run out, so having multiple filters on hand is a good idea.
Long term – After filtration ceases to work, whether by lack of filters or when water sources dry up or become too dangerous, you need to find a long term source for drinking water. Digging a well now is the most feasible option, as they will be difficult to construct without modern technology and tools.
A lack of drinking water can be deadly, as can be drinking unsafe water full of bacteria or other toxins. Put a plan in place now to ensure that you have enough drinking water to survive for a week, month, or if needed, a year without modern infrastructure.