Water · Reference · Basic
Treat Cloudy or Cold Water Safely
Sediment and low temperature make chemical treatment harder. Prepare the water, choose a dependable method, and prevent recontamination.
This is for educational purposes only. Not professional medical, electrical, or safety advice.
Warning
A cloth prefilter is not a disinfectant. Cold or cloudy water can make chemical treatment less dependable; use the product's actual directions.
- 01
Reject chemical contamination
Do not try to rescue water suspected of fuel spills, toxic chemicals or radioactive contamination. Change sources and follow public-health instructions; filtering and boiling are not a solution for those hazards.
- 02
Let sediment settle
Leave cloudy water undisturbed until sediment drops, then gently pour the clearer upper water into another container. Avoid stirring up the bottom. There is no universal settling time for every source.
- 03
Prefilter visible particles
Pass water through a clean cloth, paper towel or coffee filter when available. This preparation improves clarity but does not make the water safe to drink. Use a rated water filter when your plan requires pathogen removal.
- 04
Boil when possible
Bring clear water to a rolling boil for 1 minute, or 3 minutes above 6,500 feet. Let it cool covered without adding untreated ice. Use stoves outdoors, away from enclosed spaces.
- 05
Respect chemical contact time
If boiling is not possible, use a labeled drinking-water disinfectant and follow its directions for cold or turbid water. Cold conditions may need longer contact time. If the product does not cover your conditions, choose another method rather than guessing.
- 06
Protect the clean side
Keep untreated water separate from treated water. Use clean containers and caps; do not dip dirty cups or hands into the supply. Clean-looking water is not proof of safety.