Emergency Water Guide

Water is the single most important resource in any emergency. You can survive weeks without food but only a few days without clean drinking water. The World Health Organization (WHO) sets a minimum of 2 litres per person per day for drinking, and the UK government's gov.uk/prepare campaign recommends storing enough to manage for at least 72 hours. In real-world UK events like the Devon Cryptosporidium boil water notice (May 2024, ~16,000 properties) and Storm Babet flooding (October 2023), having 7 full days of stored water has proved invaluable.

In the United Kingdom, storms, floods, and infrastructure failures regularly leave communities without safe drinking water for days. South West Water issued a boil water notice across Brixham and surrounding areas in May 2024 after Cryptosporidium contamination. Storm Babet (October 2023) flooded treatment works in eastern Scotland. These are not hypothetical scenarios — they happen every year and affect households who never thought they were at risk.

How Much Water Do You Actually Need

The 2-litre-per-person-per-day figure from WHO is a drinking minimum. In practice, your needs depend on several factors:

• Heatwaves or physical activity: increases to 3 litres per person per day. The July 2022 heatwave hit 40.3 °C at Coningsby, Lincolnshire — the UK's first ever 40 °C reading — and dehydration was a real threat.
• Young children and elderly: need special attention. Children dehydrate faster, and older people often do not feel thirsty until they are already dehydrated.
• Pets: a medium dog needs about 0.5 litres per day. Do not forget to include them.
• Cooking and basic hygiene: rice and pasta need 1 to 1.5 litres per portion to cook, so add cooking water on top of the drinking baseline.

For a family of 4 over 7 days, the maths is: 4 people x 3 litres x 7 days = at least 84 litres. That sounds like a lot, but it is just four stackable 20-litre food-grade containers. If you prefer not to do the calculation by hand, our emergency planner sizes the exact amount for your household.

How to Store Water Properly

The simplest approach is commercially bottled water. It is sealed, treated, and lasts 1 to 2 years. For larger volumes, food-grade water containers in 5-litre or 20-litre sizes are practical and stackable.

• Store in a cool, dark location away from direct sunlight and chemicals
• Label each container with the fill date
• Rotate tap-filled containers every 6 months
• Keep at least some water in portable containers for evacuation
• Avoid unheated garages and outbuildings — PET bottles split when they freeze, and Storm Eowyn (January 2025) brought sustained lows of -8 °C across Scotland and Northern Ireland

Water Purification Methods

Even with stored water, you should have a backup purification method in case your supply runs out:

• Water purification tablets: Aquatabs, Puritabs or chlorine dioxide tablets are lightweight, inexpensive, and effective against bacteria, viruses and protozoa. Follow the dosage on the pack.
• Portable water filters: a LifeStraw, Sawyer Squeeze or Doulton Ultracarb removes bacteria and protozoa. Excellent for extended scenarios.
• Boiling: bring water to a rolling boil for at least 1 minute. The oldest and most reliable method (NHS and WHO guidance for the UK).
• Household bleach: 2 drops of unscented UK Domestos or own-brand bleach (4.5 to 5% sodium hypochlorite) per litre, wait 30 minutes. Never use scented or thickened "gel" bleach.

Special Considerations

• If you have an infant, store extra water for formula preparation — NHS guidance is to use freshly boiled water cooled to no less than 70 °C for powdered formula
• Keep a filter or tablets in your go-bag for evacuation scenarios
• If you have a megaflo or vented hot water cylinder it can hold 80 to 200 litres of usable water — combi boilers have no tank, so this only applies to homes with a cylinder
• Never drink floodwater or water from swimming pools without proper treatment