Source priority

• Stored water first, then rainwater, then flowing surface water, then groundwater, then stagnant water last.
• Avoid any water with a fuel or oil film, a bleach-like smell, floating debris, or water from radiators and heating systems.
• Springs and fast-moving streams above any settlement are the safest untreated sources.

Boiling

• Bring to a rolling boil for 1 full minute — 3 minutes above 6,500 ft elevation.
• Boiling kills pathogens but does not remove chemicals; filter first if the water is cloudy.
• Boiled water tastes flat — pour it back and forth between two clean containers to aerate.

Chemical disinfection

• Unscented household bleach (8.25%): 2 drops per quart for clear water, 4 drops if cloudy.
• Stir and let stand 30 minutes. A faint chlorine smell should remain — if not, repeat once.
• Do not use scented, color-safe, or splashless bleach.

Filtration & distillation

• Ceramic and carbon filters remove sediment, protozoa, and many bacteria — backflush them regularly.
• Filters alone do not remove viruses; combine with boiling or chemical treatment.
• Distill (boil and condense the steam) when chemical or radiological contamination is possible.

Storage

• Plan 1 gallon per person per day — at least 2 quarts for drinking, the rest for hygiene and cooking.
• Rotate stored water every 6 to 12 months; mark every container with the fill date.
• Keep water out of sunlight in food-grade containers, and never reuse a container that held chemicals.