Emergency Prepared

Water calculator

See how much water to store for your household, with the source for each figure. Storing tap water is the cheapest way to start.

DRAFT: The baby and pet amounts and the storage costs is waiting for review. Figures and wording may change before launch.

Your household

The results below update as you answer. Nothing you choose leaves your browser.

Adults and children. Do not count babies under 12 months here.
We add a little extra water for each baby, for washing bottles and hands.
Do you have pets?
How many days do you want to plan for?Be Ready suggests 3 days. Some people, especially in rural areas, plan for 7.

How much water to store

Drinking water minimum

9 litresfor 3 days. That is about 5 two-litre bottles.

Source: Be Ready (UK Government), which suggests 3 litres per person per day for drinking.

Comfortable amount, including cooking and washing

30 litresfor 3 days. That is about 6 five-litre containers.

Source: GOV.UK Prepare (earlier guidance, now replaced by Be Ready), which suggested 10 litres per person per day.

Store tap water first

UK tap water is safe to drink. The cheapest way to be ready is to fill clean bottles or containers with tap water, seal them, label them with the date, and swap them for fresh water every 6 months. Buying anything is optional.

Ways to store water compared

Storage options by cost, space and shelf life
OptionCost for your comfortable amountSpaceShelf life
Tap water in clean bottlesStart here£0 to £2Almost free if you reuse clean drinks bottles. New food-safe containers cost about £5 to £15 each.About the size of the water itself. 20 litres fits in a box roughly 30 by 30 by 25 cm.Swap it for fresh tap water every 6 months.
Five-year emergency water pouches£90 to £180Much more expensive per litre than tap water.Flat pouches pack tightly into a bag or boot.Check the manufacturer's stated shelf life on the packet. Many say 5 years.
Water butt with a filter£30 to £80For one 100 to 200 litre water butt, whatever the size of your household. A suitable filter is extra.Needs outdoor space and a downpipe.Refills when it rains. Keep the lid on and clean it once a year.

Tap water in clean bottles: Start here. UK tap water is safe to drink, and storing it costs almost nothing. Good for: drinking, cooking and washing.

Five-year emergency water pouches: Optional. Useful for a grab bag or car, where you cannot swap water often. Good for: drinking.

Water butt with a filter: Optional. Collects rainwater for flushing toilets and washing. Only drink it if your filter's manufacturer says the filter is made for that. Good for: flushing toilets and washing. drinking only with a filter made for it.

DRAFT: Costs and the baby and pet amounts are waiting for review by the site owner.

Read our guide to how much water to store and how to store it.

Last reviewed: .