Be Ready UK: How Much Water to Store for 3 Days
The UK government's Be Ready campaign (launched by the Cabinet Office in October 2026) asks households to keep at least 72 hours of essential supplies. For drinking water that means roughly 3 litres per person per day.
The K Series 2.25-gallon gravity system runs on gravity alone, with no power, pump, or battery.
What the Be Ready guidance actually says
Be Ready is a preparedness, not a panic, programme. It recommends that every UK household hold a short reserve of essentials — water, long-life food, a torch, a radio, some cash, and a paper copy of important contacts — enough to ride out roughly three days if services are interrupted.
For water, the figure used is 3 litres per person per day. That covers drinking and very basic hygiene. The campaign is explicit that this is about everyday resilience (storms, local flooding, power or telecoms outages) rather than any single predicted event.
Work out your household's water store
Multiply the number of people in your home by 3 litres, then by 3 days. The table below gives common household sizes:
| People in home | Per day | 3-day store |
|---|---|---|
| 1 | 3 L | 9 L |
| 2 | 6 L | 18 L |
| 3 | 9 L | 27 L |
| 4 | 12 L | 36 L |
| 5 | 15 L | 45 L |
If anyone is pregnant, ill, or you have pets, add extra. Hot weather and physical exertion also raise the need above 3 litres.
Storing bought water
Sealed shop-bought water in PET bottles is the simplest start. Keep bottles cool, dark and away from chemicals. Most have a best-before date; rotate them into normal use before that date and replace. Avoid leaving bottles in direct sun, which can affect taste and the plastic.
For larger reserves, food-grade containers (marked as safe for drinking water) work well. Wash and rinse them with a little mild bleach solution, then fresh water, before the first fill.
The catch with stockpiling
Stored water has two limits: it takes up space, and it doesn't last forever without rotation. Most households don't want 36+ litres of bottles permanently lining a cupboard, and forgetting to rotate means you discover expired water exactly when you need it.
This is where a different approach helps.
Reduce the burden with a no-electricity gravity filter
A gravity water filter treats water using gravity alone — no power, no pumps, no batteries. In a disruption, mains water may still be available but advisory notices common (“boil before use”), or you may want to make collected rainwater or other found water safer to drink. A gravity filter lets you do that on demand instead of relying only on a fixed stockpile.
Two points of honesty: a gravity filter is a complement to a stored reserve, not a replacement for the official 72-hour advice on day one. And it is not magic — see the limitations in our countertop filter guide and the PFAS article for what these systems do and don't remove.
A gravity filter treats tap or collected rainwater on demand, reducing how much water you must stockpile.
How it fits with your other Be Ready items
Water is only one line on the Be Ready list. Pair your store with the other recommended items and you have a practical 72-hour kit. If you keep a small rotating water reserve and a gravity filter as a treatment backup, you cover both “ready now” and “runs out” scenarios without filling a shed.
Recommended emergency backup water filter
Lighten your emergency storage burden with a non-electric, stainless steel gravity filtration system — available in your regional store:
- UK customers (£ GBP): Explore the Purewell K Series 2.25-Gallon Gravity Filter (UK Store)
- US customers ($ USD): Explore the Purewell K Series 2.25-Gallon Gravity Filter (US Store)
- Europe (€ EUR): Explore the Purewell K Series 2.25-Gallon Gravity Filter (EU Store)
Specification note: activated carbon with silver ions + 0.01-micron ultrafiltration reduces bacteria, protozoa, and chlorine taste without electricity. It does not remove viruses or PFAS, and is not a desalinator. Also consider the BO Series 2.25-gallon for a lower-cost entry.
Frequently Asked Questions
How much water should I store for Be Ready UK?
The campaign figure is about 3 litres per person per day for at least 72 hours. For a family of four that is roughly 36 litres. Add more for hot weather, illness, or pets.
Does Be Ready say I must buy special water containers?
No. Sealed shop-bought bottles are fine to start. Food-grade containers help for larger reserves — clean them before first use and keep them cool and dark.
Can a water filter replace my stored water?
No. Keep the recommended short reserve for immediate use. A gravity filter is a treatment backup for top-ups from the tap or collected rainwater if a disruption lasts longer than your store.
Do gravity filters need electricity?
The ones we discuss here do not. They run on gravity alone, which is why they suit power-cut and off-grid scenarios.
How long does stored bottled water last?
Check the best-before date and rotate. Store cool, dark, and away from chemicals; discard any bottle that looks cloudy or smells off.
Is rainwater safe to drink after filtering?
Rainwater can carry debris, bird droppings, and roof contaminants. A gravity filter reduces many impurities but is not a guarantee against all hazards; boil first for highest-risk sources and follow official advice.
Where can I read the official guidance?
The UK government publishes preparedness advice at gov.uk/beready. Treat this article as a practical companion, not a substitute for official guidance.
Which Purewell filter suits emergency use?
The K Series 2.25-gallon and BO Series 2.25-gallon gravity systems need no electricity and treat water by multi-stage filtration. See the product pages for specifications.
