You can filter a river — but only if you live long enough to reach it. Store water first.

The widely used baseline is one gallon per person per day, covering both drinking and basic hygiene, with a three-day minimum for short emergencies and a two-week supply for extended grid-down events. Children, nursing mothers, the sick, and anyone in hot climates or doing hard physical work need noticeably more, so the guide helps you size a realistic household total rather than a single flat number.

Use food-grade containers made for water, such as HDPE barrels, stackable jugs, or thoroughly sanitized bottles, and never reuse old milk jugs or anything that held chemicals. The guide covers cleaning and sanitizing containers before filling, why opaque containers slow algae growth, and storing barrels up off bare concrete so they do not pick up odors or leach contaminants over months of storage.

Water itself does not spoil, but it can pick up bacteria, algae, or off-flavors from its container and surroundings. Tap water kept in clean food-grade containers stays good for roughly six to twelve months before rotation, while commercially sealed bottled water is usually dated for one to two years. The guide explains dating each container and rotating stock so nothing sits untested and forgotten for years.

Fill clean containers with potable tap water, keep them sealed, and store them somewhere cool, dark, and away from fuel, pesticides, and direct sunlight that speeds bacterial and algae growth. For questionable or long-held water, the guide covers light chlorination to disinfect and how to freshen flat-tasting water by pouring it back and forth between clean containers to reaerate it before you drink it.