How much water does your household need for 72 hours?

Start with people, not containers

Count adults and children in the household you are planning for. Two adults and one child means three people: 3 × 3 litres × 3 days = 27 litres of drinking water. Four people means 36 litres. READY72 shows this calculation so you can check it rather than accept an unexplained recommendation.

This figure is drinking water only. Be Ready explicitly says more is needed for cooking and washing. It does not give a single extra amount that fits every household, so we do not add a made-up percentage. Pets also need their own water. If someone has specific clinical fluid guidance, continue to follow it and ask their care team about disruption planning.

Turn the total into a manageable storage plan

Check existing unopened drinking-water bottles first, including their printed storage instructions and dates. If 27 litres sounds like a lot, split the task into a cupboard check and a gradual top-up rather than one expensive shopping trip. You do not need a purpose-built emergency container to start.

Choose a practical, accessible location away from avoidable heat and contamination. Heavy containers can be difficult to lift and awkward in a small flat. Several smaller bottles may suit your household better. If you use a refillable container, use one intended for drinking water and follow its manufacturer’s cleaning, filling and storage instructions; this guide does not provide a universal storage lifetime for home-filled water.

Make “done” mean enough, not just owned

Write down your target and how much usable drinking water you have available. A two-litre bottle is useful progress, but it is not a completed 27-litre household target. Mark the checklist action complete when you have checked the amount against the people in your plan. If more people join the household, recalculate.

• People in this plan: ___
• Three-day drinking-water target: people × 9 litres = ___
• Usable drinking water already available: ___
• Separate cooking, washing and pet-water arrangements: ___

Review it without wasting it

Be Ready suggests checking emergency supplies every six months. Put that review beside a routine you already remember. Check labels and condition, use water within the applicable instructions, and replace what you use. During an actual supply interruption, follow your water supplier’s instructions about water safety; do not assume stored water or boiling solves every type of contamination.