Water Supply Outage: What to Prepare
WATER YOU HAVE. WATER TO PLAN.
How much drinking water could your household cover?
Enter how many people you are planning for, for how long, and the litres of safely stored, drinkable water you actually have. This uses broad UK Government planning references—not an individual prescription or an assessment of water quality.
Count your current safely stored drinking water to begin.
Results appear here after you select Show My Water Plan.
Important: drinking-water references of 2.5–3 litres per person per day do not necessarily cover cooking, washing, pets, medical needs or hot weather. The UK Government also cites 10 litres per person per day as a more comfortable reference including basic cooking and hygiene. Never assume a filter makes an unknown water source safe.
Source: UK Government Prepare campaign. The tool runs only in your browser, sends no answers to Go Prepare and doesn't change your basket.
Plan for a temporary interruption to your mains water supply without guessing that a household water filter, untreated stream or stored container is automatically safe.
Start with your people and likely duration
The UK Government Prepare campaign cites a minimum of around 2.5–3 litres of drinking water per person per day for survival, and explains that around 10 litres per person per day is more comfortable when allowing for some basic cooking and hygiene. These are planning reference points, not individual medical requirements. Extra water may be needed for infants, pets, particular health needs or hot weather.
A simple household example
For four people over three days, the 2.5–3 litre drinking-water reference equates to 30–36 litres for drinking alone. The 10-litre wider planning reference gives 120 litres for drinking plus some other basic uses. Consider the weight and safe storage of water containers.
What should you do before an outage?
- Check the safe drinking-water supply you already have and count containers suitable for potable water.
- Read storage instructions, check seals, dates, cleanliness and whether you can lift full containers.
- Know your supplier’s incident contact and check official notices if the supply is affected.
- Have ways to maintain hand hygiene, particularly when caring for children.
- Plan for pets and individual requirements.
When the supply is interrupted or water is declared unsafe
Follow the water supplier’s advice about whether water can be used, boiled, filtered or must not be used at all. Do not assume boiling or a portable filter removes chemical contamination. If a boil-water notice is in force, follow the exact current instructions. Use your existing safe drinking water until the supply is confirmed suitable.
Spend sensibly
Begin with safe reusable water containers and properly stored bottled water if suitable. Specialist filters, UV devices or treatment products require exact evidence of which hazards they address; do not buy them on generic claims. Consider needs for carrying water and replacing or rotating it.
Related tools
72-hour plan · Food planning · Long-term food and water.
Where to get updates and extra support
Across the UK: Check your own water supplier’s current incident updates, emergency number, boil-water notices and support for customers with additional needs. Keep its contact details printed and register for any suitable priority support service in advance.
If the supplier issues a boil-water or do-not-drink notice, follow the specific notice and do not improvise with unverified filters or chemical treatments.
Official reference
UK Government Prepare campaign.
Guide reviewed 14 October 2026. General planning guidance—not a guarantee of safety. Check current official advice and the circumstances of your household.