Storing water and planning how much you need
Use this when: You are building reserves for a water or power outage.
Current official instructions for your area take priority. UK Ready is an independent information site, not a government service. This guide is written from the official sources listed below; it has not yet had a specialist review. Sources checked 24 October 2026.
ACTION SUMMARY
- 1Store 3 litres of drinking water per person per day for three days — 9 litres per person.
- 2Keep extra water for cooking, washing, feeding, medical equipment and pets separately.
- 3Use sealed bottled water or clean food-grade containers kept cool, dark and away from chemicals.
- 4Label the fill date on your own containers and replace them as the product instructions say.
- 5Never count radiators, boilers, floodwater, ponds or pools as drinking water.
In detail
The government's Be Ready checklist (updated 22 October 2026) specifies 3 litres of drinking water per person per day for three days. Cooking and washing need additional water. Extra needs may include feeding preparation, medical equipment, pets and hot weather.
UK Ready's calculator uses people × 3 litres × 3 days as the drinking-water figure and keeps any extras separate. This is a storage planning figure, not a medical drinking prescription. Babies, people with fluid restrictions and people with illness need individual care advice. Do not tell a baby to drink an adult water allowance or tell someone with heart or kidney disease to ignore their treatment plan.
Drinking water for three days
| People in the household | Drinking water for three days |
|---|---|
| 1 | 9 litres |
| 2 | 18 litres |
| 4 | 36 litres |
| 6 | 54 litres |
These are calculated examples, not a requirement to buy or carry those volumes. Start with what is affordable and can be stored safely, and understand how to obtain additional water if an interruption lasts longer. See food and water for three days.
Use sealed commercial drinking water or suitable clean food-grade storage containers. Follow product storage and replacement instructions. Keep water cool, away from sunlight and away from chemicals. Label fill dates for your own containers. Never reuse a container that previously held chemicals or fuel.
Keep quantities manageable so someone with reduced strength can lift them. Distribute heavy containers safely; do not pile large loads on shelving or obstruct exits. Keep a little accessible rather than storing every bottle in a hard-to-reach loft or an area likely to flood.
Water sources to avoid: Central heating radiators and heating boilers are not drinking-water stores. Floodwater, ornamental ponds, swimming pools and water collected outdoors in a contamination event must not be treated as safe drinking water. Obtain official or specialist advice for a private well or borehole rather than improvising treatment.
Planning for longer? See the two week emergency food and essentials checklist — an optional fourteen-day extension of the three-day starting point.
Official sources
This guidance is an editorial explanation of official UK advice. Always follow instructions from the authorities.
- UK Government Be Ready: Be ready for emergencies Covers: UKPublished: Not statedChecked: 2026-10-24
- UK Government Be Ready: Get prepared for emergencies Covers: UKPublished: Not stated in the material retrievedChecked: 2026-10-13
- US Centers for Disease Control and Prevention: How to Make Water Safe in an Emergency Covers: US supplementaryPublished: 2024-09-19Checked: 2026-10-13US source — supplementary
- UK Government Be Ready: Water supply interruptions or outages Covers: UKPublished: Not stated in the material retrievedChecked: 2026-10-13
US sources are used only for the scientific or blast-protection points they support. They never replace UK instructions, numbers or agencies.
Adapted Crown copyright material is used under the Open Government Licence v3.0. No government endorsement is implied.
Common questions
How much emergency water should I store?
The government's Be Ready checklist specifies 3 litres of drinking water per person per day over three days. Cooking and washing need additional water, and individual needs vary.
Is three litres a drinking instruction for babies?
No. It is a general storage planning figure, not infant feeding or medical advice. Babies and people with clinical fluid restrictions need their individual care advice.
Can I use water from a radiator or heating boiler?
No. Water in a central heating system is not a safe drinking-water reserve. Do not confuse it with a protected potable supply.
Related guides
- Household preparationBuilding a realistic emergency kit
- Nuclear and radiological incidentsFood, water and recovery after radioactive contamination
- Chemicals and water safetySuspected poisoning or deliberate contamination of water
- Chemicals and water safetyUnderstanding water notices and finding safe supplies
- Power and essential servicesManaging a power cut lasting days or weeks