Free household planning tool
72-hour household water calculator
Work out a simple drinking-water planning quantity for a short disruption. Adjust the daily litres to suit your household and circumstances rather than treating one number as universal.
Planning quantity
36.0 litres
For 4 people × 3 L/day × 3 days.
Storage first, filtration second
A filter is not a substitute for having water available. Start with sensible stored drinking water, rotate it, and use filtration as an additional tool where it solves a defined problem.
This is a planning calculator, not an official emergency-water requirement. Needs vary with health, weather, activity, food preparation and other circumstances.