Emergency Water Storage Calculator

Who are you preparing for?

Start with the number of people and pets in the household. At least one household member is required.

1

Household members

Enter the total number of people who need to be included in the water plan.

Household members

Pets

Pet needs are added separately using an editable daily allowance in the next step.

Pets

Property type

This controls whether outdoor water-butt storage is included later in the calculator.

HouseWater-butt options available Flat or apartmentPortable storage only

Set your sufficiency target

Choose how many days you want your stored water to cover, then use the UK Government planning figures or enter your household’s own daily consumption.

2

Target duration

3 daysShort disruption 7 daysOne week 14 daysExtended cover

Or use a custom number of days

Calculation method

Use the published emergency-planning allowance, or switch to advanced mode to reflect your household’s normal consumption.

UK Government figures3L drinking water and 7L additional water per person per day Set my own consumptionEnter drinking-water, non-potable and toilet-flushing use

Current target estimate 18L drinking + 42L hygiene

Drinking-quality water already stored

Enter full, usable containers of drinking water. This total is reserved for drinking, food preparation and pets.

3

Quick add common UK multipacks

Each click adds one complete retail pack to your stored-water total.

Drinking water currently stored0L

Non-potable water already available

Add portable containers and any water butts or tanks used for toilet flushing, cleaning and other suitable non-drinking uses.

4

Portable containers

Enter full containers reserved for non-drinking use.

Water butts and tanks

Select a common UK size, or choose a custom capacity. Add each water butt separately.

Total non-potable water available0L

Do not count untreated rainwater or unknown water as drinking water. Use appropriate hygiene controls and follow local public-health advice during an incident.

Emergency Water Storage Calculator

Your water preparedness result

Drinking-water and non-potable supplies are assessed separately so a large water butt cannot conceal a drinking-water shortage.

5

Drinking-quality water

0%

of your selected 3-day target currently stored

Target0L
Stored0L
Current cover3L per person per day0 days
Ration cover1.5L per person per day0 days
Shortfall / surplus0L

Hygiene and sanitation water

0%

of your selected 3-day target currently available

Target0L
Available now0L
Current cover7L per person per day0 days
Ration cover3.5L per person per day0 days
Shortfall / surplus0L

Planning basis: UK Government Prepare guidance states that 2.5–3 litres of drinking water per person per day is a survival minimum, while 10 litres per person per day provides more comfort for basic cooking and hygiene. The separate ration-cover figures use half of whichever daily allowances are selected. In advanced mode, toilet-flushing demand is based on the household estimate entered by the user and assumes a 6-litre cistern. These are illustrative emergency-rationing figures, not separate Government recommendations. Extra water may be required for pets, baby formula and medical devices. Review the official guidance at GOV.UK Prepare. This calculator is a planning aid, not medical or public-health advice.

Who are you preparing for?

Household members

Pets

Property type

Set your sufficiency target

Target duration

Calculation method

Advanced consumption settings

Pet water allowance

Drinking-quality water already stored

Quick add common UK multipacks

Non-potable water already available

Portable containers

Water butts and tanks

Portable storage only

Your water preparedness result

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