Water · Reference · Basic
Disinfect Water: Boil, Bleach, Iodine, SODIS
Compare boiling and chemical disinfection, with product-specific directions and important limits for water safety.
This is for educational purposes only. Not professional medical, electrical, or safety advice.
Warning
None of these remove chemicals, heavy metals or fuel. Iodine does not reliably kill Cryptosporidium. Choose the cleanest source and follow local advisories and product labels.
- 01
Boil
Rolling boil for 1 minute; 3 minutes above 6,500 ft (2,000 m). The most reliable method.
- 02
Bleach
Per gallon of clear water: 8 drops of 6% or 6 drops of 8.25% unscented bleach. Double for cloudy water. Wait 30 minutes; it should smell faintly of chlorine.
- 03
Avoid improvised pool chemicals
Do not substitute a random pool-shock product: concentration and additives vary. Use a product labeled for drinking-water treatment and its exact directions; never mix disinfectants.
- 04
Iodine
Use only a labeled drinking-water iodine disinfectant and follow its exact dose, volume and contact time, including cold/cloudy conditions. Iodine is not reliable against Cryptosporidium. Avoid during pregnancy, with thyroid disease or a known treatment-product allergy. Short-term only, not continuous use or beyond a few weeks. Iodized salt and supplements do not disinfect water.
- 05
SODIS (sunlight)
Fill clear PET bottles (2 L or less) with clear water, lay on a reflective surface in full sun for 6 hours (2 days if cloudy).