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Water for emergencies

Water is the weakest point in many UK household plans. How much to store, how to store it safely, and what to do if the mains is disrupted.

WHAT TO DO NOW

  1. 1Store commercially bottled water — aim for 72 hours first (about 3 litres per person per day), then build towards 7 days.
  2. 2Build stocks gradually — water is heavy (about 1kg per litre); store safely in more than one place without blocking exits.
  3. 3Keep extra water for babies, pets, medical devices and hygiene.
  4. 4If the mains is disrupted, use safe stored water first for drinking, medicines, handwashing, cooking and baby formula.
  5. 5Follow your water company's boil-water, do-not-drink or do-not-use notice exactly — they mean different things.

What not to do

  • Do not rely on self-filled containers for long-term storage — use commercially bottled water.
  • Do not drink rain-butt water (it may be useful for flushing or plants).
  • Do not boil water for infant formula if a do-not-drink notice applies — use ready-to-feed formula where possible.

What is it?

UK Prepare guidance (citing WHO survival figures) cites 2.5–3 litres of drinking water per person per day as a minimum, with about 10 litres per person per day giving more comfort once basic cooking and hygiene are included. In the 2026 Cabinet Office survey, only 4% of households had three or more days of bottled water.

What might happen?

A mains interruption can mean no drinking water, washing or toilet flushing. Notices may be issued: 'boil water', 'do not drink' or 'do not use' — each means something different, so read them carefully.

First 10 minutes

Check your water company's website/social media for the cause. If you still have supply and no notice is in force, fill clean containers.

First hour

Drinking-water minimums: 1 person ≈ 9L for 3 days / 21L for 7 days; 2 people ≈ 18L / 42L; 4 people ≈ 36L / 84L; 6 people ≈ 54L / 126L. These are drinking-water only — add more for hygiene, babies, pets and medical needs.

First 24 hours

Ration stored water sensibly and prioritise drinking, medicines and infant feeds. Collect bottled water from official points if provided.

If it continues for several days

For longer interruptions, water companies must support vulnerable customers on the Priority Services Register with bottled-water deliveries. Follow official advice on when supply and quality are restored, and flush pipes afterwards as advised.

Children

Keep babies' feeds safe — use ready-to-feed formula if you cannot safely boil water; ask your health visitor or water company if unsure.

Older & vulnerable people

Register vulnerable people on the water company's Priority Services Register for bottled-water delivery.

Pets

Provide pets with safe (bottled or appropriately treated) water too.

Communications

Keep your water company's number to hand and check their channels for updates.

Official sources

This guidance is an editorial explanation of official UK advice. Always follow instructions from the authorities.

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