Plan for at least 1 gallon per person per day for drinking and basic sanitation. That is the Ready.gov baseline. Three days is a minimum; two weeks at home is better if services are cut off.
A simple household table
| Household | 3 days | 2 weeks |
|---|---|---|
| 1 person | 3 gal | 14 gal |
| 2 people | 6 gal | 28 gal |
| 4 people | 12 gal | 56 gal |
| 4 people + 2 pets | 15–18 gal | 70–84 gal |
Add extra for heat, pregnancy, children, special needs, and pets. Do not ration drinking water to the point of dehydration.
Store it safely
Use food-grade containers with tight lids. Keep them in a cool, dark place. Label the fill date and rotate every six months.
Do not use containers that held fuel, pesticides, or unknown chemicals. A container that smells like its last contents is not a water container.
Make water safe
Boil
Bring water to a rolling boil for 1 minute. At elevations above 6,500 ft, boil for 3 minutes. Let it cool covered before drinking or storing.
Boiling kills bacteria, viruses, and parasites. It does not remove chemicals or fuel.
Filter
Filter cloudy water through a clean cloth, coffee filter, or commercial filter before disinfecting. Sediment can protect germs from disinfectants and clog filters.
A cloth filter alone does not make water safe.
Chemical treatment
Use unscented household chlorine bleach or water-treatment tablets made for drinking water. Follow the product label or CDC guidance for dose and contact time. If you cannot measure, boil instead.
Do not use pool chlorine, scented bleach, or unknown chemicals.
UV and solar
UV purifiers need clear water and the correct dose. Solar disinfection works best with clear PET bottles in strong sun for at least 6 hours (2 days if cloudy). These are backup methods, not a fix for chemical contamination.
When not to drink it
Do not drink water with a fuel, solvent, or chemical smell, or a rainbow sheen. Boiling does not remove chemicals and can concentrate them.
Floodwater can carry sewage, chemicals, and debris. Treat it as contaminated.
A two-week plan
- Store at least 1 gallon per person per day.
- Add a way to boil: pot, stove, or fire.
- Add a filter or chemical treatment as backup.
- Keep a clean funnel, cloth, and food-grade containers.
- Rotate and label.
For the field version, see How much water you need, Store water safely, and Boil water in Fieldry. The app keeps the quantities and steps offline.
Sources
- Ready.gov — Water: https://www.ready.gov/water
- CDC — Boil Water Advisory: https://www.cdc.gov/healthywater/emergency/drinking/boil-water-advisory.html
- CDC — Water Treatment: https://www.cdc.gov/water-emergency/about/index.html