Size the reserve around people and duration

The U.S. CDC advises storing at least 1 gallon per person per day for three days and trying for a two-week supply when possible. Treat this as U.S. emergency-planning guidance, not a universal consumption guarantee. Hot climates, pregnancy, illness, and pets can increase needs. Include water for cooking and brushing teeth as well as drinking. CDC describes unopened commercially bottled water as the safest and most reliable emergency source; check its printed date and keep it sealed until needed.

Make container hygiene part of the plan

For water filled at home, use a food-grade container. If one is unavailable, CDC advises a durable, non-breakable container with a tight lid and preferably a narrow opening. Never reuse a container that held toxic chemicals. Wash and sanitize it using the CDC procedure, label it as drinking water with the fill date, and store it cool, away from sunlight and fuels or pesticides. Replace self-filled water every six months. When dispensing, use a clean scoop and keep hands out of the water and container so the stored supply is not contaminated during use.

Respond to a water advisory without guessing

When authorities say tap water is unsafe, use an approved safe source for drinking, food preparation, ice, brushing teeth, and hygiene. Boiling is effective against many germs, but it cannot remove fuel, toxic chemicals, or radioactive material. CDC’s boiling instruction is a rolling boil for one minute, or three minutes above 6,500 feet; local health-department directions take priority. Portable filters have different capabilities and may not remove viruses, so filtration alone is not proof that emergency water is safe.

Expert perspective: distinguish storage advice from treatment orders

The American Red Cross offers an institutional disaster-preparedness checklist: keep water in a portable kit for use at home or during evacuation, and add infant, medical, or pet supplies as needed. Treat the CDC’s gallon figure as a planning baseline, then account for duration, climate, storage space, and local emergency plans. If chemical contamination is suspected, do not try to fix it by boiling or adding bleach: use bottled or another specifically approved source and contact the health department. Treatment instructions depend on the contaminant, water clarity, and the product label. The CDC quantities and U.S. elevation threshold should not be transplanted into another country’s water rules without local confirmation.

Sources and references: How to Create an Emergency Water Supply | CDC / What Do You Need In a Survival Kit? | American Red Cross