Make the water safe to drink.

You have the water — this tells you what makes it safe, and exactly how much treatment to use.

How to use it

• Enter the amount of water and pick a method: plain bleach, pool shock, iodine, chlorine dioxide, boiling, or a filter.
• Set your altitude for the correct boil time, or your product form (tablets or two-part drops) for chlorine dioxide.

What you get

• The exact dose — drops of bleach or iodine per gallon, the pool-shock ratio, or chlorine-dioxide tablets/drops with their wait times — plus the boil time for your elevation and roughly how long a filter lasts.

Tips

• Double the bleach or iodine dose for cloudy or cold water, and let it stand at least 30 minutes.
• Iodine is a short-term fix only — not for pregnancy, thyroid conditions, iodine allergy, or more than a few weeks at a time.
• Chlorine dioxide is the only chemical here that kills Cryptosporidium, but it needs up to 4 hours of contact in cold or dirty water.
• Boiling is the most reliable method when you can spare the fuel.

Good to know

Follows EPA and CDC emergency guidance and the product labels. Bleach, pool shock, and iodine don’t kill Cryptosporidium — only boiling, a rated filter, or chlorine dioxide (at its long contact time) will. No chemical removes chemical pollutants or heavy metals; for those you need filtration or distillation.