How much water do I need per person per day in a UK emergency?

Using EFSA/NHS hydration guidelines plus emergency cooking and hygiene allowances, an adult male requires 4.5L/day (2.5L drinking + 0.5L cooking + 1.5L hygiene) and an adult female requires 4.0L/day (2.0L drinking + 0.5L cooking + 1.5L hygiene). For a 72-hour (3-day) emergency, store at least 12 to 13.5 litres per adult.

Why are baby formula and pet food calculated separately?

In a real household emergency, adult pasta or tinned beans cannot feed a 6-month-old infant or a cat. PrepTrack calculates segregated daily calorie pools for General Food (adults and children), Infant Formula/Baby Food (530–890 kcal/day), Dogs (800 kcal + 1.0L water/day), and Cats (200 kcal + 0.25L water/day).

UK Emergency Water & Food Calculator (NHS & SACN Standards)

Calculate your household's exact 72-hour, 14-day, or 30-day emergency water (litres) and food (kcal) targets.

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Interactive Household Requirement Calculator

Adjust your household members and target duration below. Calculations update live using NHS adult guidelines, SACN (2011) child/infant energy tables, and EFSA drinking + cooking + hygiene water allowances.

Target Emergency Duration Calorie Ration Level Adult Males (2,500 kcal / 2.5L drink) Adult Females (2,000 kcal / 2.0L drink) Children (1–17 yrs, SACN average) Infants (<12 months, formula pool) Dogs (800 kcal / 1.0L water per day) Cats (200 kcal / 0.25L water per day)

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NHS, SACN & EFSA Reference Table Used by PrepTrack

Unlike US calculators that use generic 2,000 kcal and 1 US gallon (3.78L) rules, PrepTrack models each person's exact age, sex, and household water breakdown:

Household Member	Daily Energy (100% Ration)	Drinking Water	Cooking + Hygiene Water	Total Daily Water	30-Day Water Target
Adult Male (18+ yrs)	2,500 kcal / day (NHS)	2.50 L	2.00 L (0.5L cook + 1.5L hygiene)	4.50 L / day	135 Litres
Adult Female (18+ yrs)	2,000 kcal / day (NHS)	2.00 L	2.00 L (0.5L cook + 1.5L hygiene)	4.00 L / day	120 Litres
Child (Age 8, SACN EAR)	1,685 kcal / day (SACN)	1.60 L	2.00 L (0.5L cook + 1.5L hygiene)	3.60 L / day	108 Litres
Infant (6 months, Segregated)	670 kcal / day (SACN Infant)	0.70 L–0.90 L	2.00 L (0.5L prep + 1.5L hygiene)	2.80 L / day	84 Litres
Dog (Medium Adult, Segregated)	800 kcal / day	1.00 L	0.00 L	1.00 L / day	30 Litres
Cat (Adult Domestic, Segregated)	200 kcal / day	0.25 L	0.00 L	0.25 L / day	7.5 Litres

Explore Our Other UK Emergency Readiness Guides

Use PrepTrack's free guides and tools to build your household resilience across food, power, water, and essential supplies.

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