Emergency water calculator
Compare a household water target with the potable water you actually hold, then choose your next action.
No account. No saved profile. Inputs reset when you leave or refresh.
03 / Your water stocktake
Check your water.
Choose your next step.
Enter a household target and your actual potable water to see what is missing.
Local advice and household needs may differ. This is not a claim of compliance with every country’s guidance.
The assumptions behind the number
This tool reuses the existing WSB app assumption of one US gallon (3.785411784 litres) per person per day for its target and coverage. The target is rounded up to whole litres for display; the gap uses the exact baseline. This people-only assumption is not a claim of compliance with every country’s guidance.
Heat, pregnancy, illness and pets can increase needs. These additions are not calculated here. Follow local water advice and plan for your household’s specific requirements.
Return paths and next tools
This tool: /prepare/water-calculator
Tools hub: /prepare
Combined overview: /prepare/household-overview
Water stocktake: /prepare/water-calculator
Food stocktake: /prepare/food-stocktake
Planning kit: /prepare/kit-builder
Battery runtime: /prepare/battery-runtime
Household plan: /prepare/household-plan
The WSB app
The WSB app connects inventory, supply coverage and your emergency plan. WSB+ adds preparedness depth.