Storing emergency water for your family: how much and how
When the water stops, shop shelves of bottled water are often the first to empty. Burst mains, contamination and storms can all cut off supply, sometimes for days. This guide explains how much water to keep for each person and pet in your family, the best way to store it, and how to make it last. It follows official advice from GOV.UK Prepare.
How much water to store per person
There is no single right number, because emergencies vary in length and people use different amounts. Official UK guidance uses two figures from the World Health Organisation:
- 2.5 to 3 litres per person per day is the minimum for drinking, to survive.
- 10 litres per person per day also covers basic cooking and hygiene, and is far more comfortable.
Plan for at least three days. Here is what that looks like for different households:
| Household | Drinking only (3 L/day) | Drinking, cooking and washing (10 L/day) |
|---|---|---|
| 1 adult | 9 litres | 30 litres |
| 2 adults | 18 litres | 60 litres |
| Family of 4 | 36 litres | 120 litres |
| Family of 5 | 45 litres | 150 litres |
A good starting point for most families is the drinking-only amount, plus a little extra. You can build towards the larger figure over time. Keep more if anyone in your home is pregnant, breastfeeding, unwell or older, or if the weather is hot.
Babies
Store ready-to-feed formula if your baby uses formula. During a water outage you may not be able to boil water or sterilise bottles. Keep extra water for washing hands before feeds.
How much water do pets need?
Pets are easy to forget. A healthy dog drinks roughly 50 to 60 ml per kilo of body weight each day, and more when it is hot or active. So:
| Dog's weight | Per day | For 3 days |
|---|---|---|
| Small (5 kg) | about 0.3 litres | about 1 litre |
| Medium (15 kg) | about 0.9 litres | about 3 litres |
| Large (30 kg) | about 1.8 litres | about 5.5 litres |
A cat needs much less, often around 200 ml a day, though cats on dry food drink more. Ask your vet if your pet has a health condition, and store pet food alongside the water.
The best way to store water
Option 1: sealed bottled water (the simplest)
GOV.UK Prepare recommends buying and storing bottled water rather than filling your own containers, because shop-bought water is sealed in food-grade bottles and keeps for longer. Supermarket multipacks are cheap and easy to stack. Check the best-before date, and use and replace the oldest packs as part of your normal shopping.
Option 2: filling your own containers
If you fill your own, do it carefully:
- Use food-grade containers only, made for drinking water. Never reuse a container that has held chemicals, cleaning products or fuel.
- Wash containers well and fill them from the cold mains tap, usually the kitchen tap.
- Seal and label them with the date.
- Replace the water about every six months. When the clocks change in spring and autumn is an easy reminder.
- Several 10 to 15 litre containers are easier to lift and pour than one large tank. A full 20-litre container weighs 20 kilos.
Where to keep it
Store water somewhere cool and dark, away from sunlight, chemicals and paint. Avoid unheated garages and sheds in winter, where containers can freeze and split. Keep a few bottles somewhere easy to reach, and a few more in your grab bag in case you have to leave home.
Water you should not drink
- Rainwater from a water butt can carry bacteria. Use it for flushing toilets or watering plants only.
- Flood water is never safe, even after boiling.
- Water from radiators or the central heating system is not safe to drink.
- If you get a boil water notice, follow your water company's instructions exactly.
Making your water last during an outage
- Keep stored water for drinking, cooking, preparing baby formula and washing hands.
- Wash hands in a bowl of water with soap rather than under a running bottle, and use hand sanitiser and wet wipes where you can.
- Use paper plates to save washing up.
- Other drinks count: soft and fizzy drinks from the cupboard are safe. Do not drink milk or fresh juice that smells off.
- Check your water company's website for bottled water stations near you.
Get extra help if you need it
If someone in your home is older, disabled, has a long-term health condition or uses medical equipment that needs water, sign up to your water company's free Priority Services Register. If you are registered, your water company will arrange other supplies for you during an outage.
Is your family's water supply ready?
Water is just one part of being ready. A water outage often comes with a power cut or a flood, so see our guides to getting through a three-day power cut and checking the flood risk for your postcode.
Our free family readiness check works out what your household needs, including children and pets, in about three minutes. It shows your readiness score and the three gaps to fix first.