How much water to store
Sources awaiting check

Emergency water storage calculator
Worked example
For 4 people for 3 days:
- Minimum to drink: 30 to 36 litres (2.5 to 3 litres per person per day).
- Comfortable, for drinking, cooking and washing: 120 litres (10 litres per person per day).
- That's 24 five-litre bottles, or the same in bigger containers.
Source: gov.uk Prepare, awaiting check; NHS, awaiting check; British Red Cross, awaiting check
This guide is for anyone who wants a small supply of water at home in case the taps stop, or the water isn't safe to drink for a while. It explains the official amounts, how to work out your household's total, and what to store it in.
You don't need to buy everything at once. A few bottles is a good start.
The short answer
Official UK advice gives two amounts of water per person per day:
- Minimum, to drink: 2.5 to 3 litres per person per day.
- Comfortable, to drink, cook and wash: 10 litres per person per day.
Plan for at least 3 days. Multiply the amount by the number of people at home and the number of days, and that's your total.
The calculator above does the sum for your household and shows how many containers that is.
Work out your total, step by step
- Count everyone at home, including children and anyone who stays regularly.
- Choose a tier. The minimum covers drinking only. If you have the space, the comfortable amount means you can also cook and wash.
- Choose how many days. Start with 3 days, as official advice suggests. You can add more later.
- Add extra for babies and pets (see below).
- Turn litres into containers. The water calculator rounds the number of containers up, so the count covers the full amount.
The calculator's worked example is a household of four planning for 3 days at the comfortable amount of 10 litres per person per day. It shows the total in litres and how many bottles of each size that makes.
Babies, pets and other household needs
Babies on powdered formula. Babies need water for their feeds too. We don't have an official figure for how much extra to keep yet, so the calculator doesn't add one. Keep some ready-made formula in your kit, because it doesn't need boiled water. For help with feeding, see the NHS.
Pets. Pets need water as well. There isn't an official figure we can use yet. Ask your vet how much your pet usually drinks in a day, and add that on.
Someone who is unwell. If someone at home has a health condition that affects how much they need to drink, ask their GP or pharmacist.
Limited space. Smaller bottles can fit in gaps in cupboards, under beds or at the back of a wardrobe. Several small containers can be easier to find room for than one big one.
If you can't lift heavy containers. Choose smaller bottles you can carry and pour comfortably. A full large container is heavy, so think about who will need to move it.
What to store it in
Use clean containers made for drinking water. When you choose them, look for:
- food-grade material, made for drinking water
- a lid that seals
- a size you can lift and pour
Bottled water Ad See water storage container on Amazon
Keep them somewhere cool and dark, away from chemicals. Our guide to storing water at home covers filling, labelling and where to keep it.
When to get help
- If your water supply stops, or the water looks or smells unusual, contact your water company. It can tell you what's happening and where to get water.
- If anyone is in immediate danger, call 999.
- If you're worried about someone's health, call NHS 111.
This guide can't tell you how your local supply is affected at any moment. Your water company is the place to check.
FAQs
How much water should I store per person?
Official advice is 2.5 to 3 litres per person per day to drink, or 10 litres if you also want to cook and wash.
How many days of water should a household keep?
Plan for at least 3 days. You can build up to that a little at a time.
How much water should I store for a baby?
There isn't an official figure we can use yet. Keep ready-made formula in your kit, and see NHS advice on feeding.
How much water should I store for a pet?
There isn't an official figure we can use yet. Ask your vet how much your pet drinks in a day and add that to your total.
Is boiling water enough to make it safe?
Follow what your water company tells you. If it asks you to boil water, it will explain what to do and for how long.
Related guides
- Storing water at homeHow to store emergency water at home safely: containers, where to keep them, and when to refresh them. Based on official UK advice.
- Emergency food listWhat food to keep at home for an emergency: no-cook tins, dry food and long-life drinks from your normal cupboard. Official UK advice, with a planner.
Sources
- Minimum drinking water per person per day (lower end) (gov.uk Prepare), awaiting check
- Minimum drinking water per person per day (upper end) (gov.uk Prepare), awaiting check
- Comfortable water per person per day (drinking, cooking, washing) (gov.uk Prepare), awaiting check
- Days of supplies to keep at home (gov.uk Prepare), awaiting check
- How often to replace stored tap water (gov.uk Prepare), awaiting check
- Extra water for a baby on powdered formula (NHS), awaiting check
- Extra water per pet (British Red Cross), awaiting check
- gov.uk Prepare emergency kit list (gov.uk Prepare), awaiting check
- Emergency services (NHS), awaiting check
- NHS non-emergency help (NHS), awaiting check
- Storing water safely at home (gov.uk Prepare), awaiting check