Field guide: safe water decisions

Water problems become health problems quickly. Treat every source as known safe, uncertain but potentially treatable, or possibly contaminated by sewage, fuel, chemicals, or radiation. Local public-health instructions take priority.

Start with known-safe water

Use sealed commercial water first, then water your utility or health authority has declared safe. Keep drinking water separate from cleaning water. Mark containers with their purpose and date; keep them closed, shaded, and away from fuel, waste, and floodwater.

Do not make a risky source look safe

Boiling and common emergency treatments can reduce many biological hazards, but do not reliably remove fuel, toxic chemicals, or radioactive material. Do not use suspected water for drinking, food, teeth, infant feeding, or wounds. Change sources and seek local advice when possible.

For uncertain water

Let cloudy water settle and separate the clearer portion. Use only a treatment method you understand: boiling, an approved device used exactly as directed, or an emergency disinfectant used exactly as labeled. Keep treated water covered. If you cannot confirm safety, conserve known-safe water rather than guessing.

Escalate early

Infants, older adults, pregnant people, and people with medical conditions may have less margin for dehydration. Seek qualified help if someone cannot keep fluids down, becomes confused, faints, or becomes seriously ill.

Scope: Original civilian guidance, not a water-quality test or replacement for a local boil-water, do-not-drink, or evacuation order.