Emergency water calculator
Choose your country, household size and duration in the main resilience check. The water target updates to the selected country source pack and shows the exact litres used in the calculation.
Water is deliberately separated from other preparedness categories because it can become the limiting factor quickly when mains supply fails.
Transparent assumptions
The methodology page lists the assumptions used, and country pages link to the official sources behind the public guidance. Where the site uses its own planning assumption rather than an official standard, it says so.
Metric and gallon conversions built in
The live calculator supports metric litres, US customary gallons and UK imperial gallons. Auto mode uses the country default, while a manual override lets you compare or enter stored water in the units you prefer.
Country guidance stays visible
Changing units does not change the underlying country guidance. The calculator converts the same canonical water quantity and keeps the source pack visible so a unit preference cannot silently alter the planning assumption.
What the water result actually tells you
The planner starts with the selected country’s baseline, multiplies it by the non-pet household count and chosen number of days, then adds only the pet-water quantity that the user explicitly enters. That produces a transparent target rather than a hidden universal assumption.
Official baseline versus enhanced reserve
The baseline option follows the country source pack. The enhanced option is intentionally labelled differently: in the UK it can use the government’s higher comfort figure, while other supported countries use a visible Home Resilience Check planning setting at twice the official baseline. That makes it possible to plan a larger reserve without presenting the larger number as government guidance.
Litres, US gallons and UK gallons
Internally the calculator stores a canonical litre value. The display layer converts that quantity into the selected units. This avoids the common error where changing a unit selector accidentally reinterprets “10” as a different quantity instead of converting it.
Water quality is a separate issue
Quantity alone does not establish that water is safe to drink. During an incident, water-company and public-health instructions about boiling, collection points or do-not-drink restrictions take priority over the stockpile arithmetic.