Emergency Water Storage UK: How Much Water Does Your Household Need?
Updated: 3 days ago
If your water supply stopped tomorrow, how long could your household manage?
Water is one of the most important parts of emergency preparedness, but it is also surprisingly easy to overlook. Unlike food or electricity, most households rely on having clean running water available whenever they need it.
When thinking about emergency water storage in the UK, the first step is working out how much drinking water your household would actually need.
A burst water main, supply interruption, flooding or another emergency can change that unexpectedly.
The good news is that emergency water storage doesn’t need to be complicated or expensive.
Here’s how to work out what your household needs.
What does UK Government guidance recommend?
The UK Government’s Prepare guidance recommends considering emergency supplies for disruption lasting a few days.
For drinking water, it gives a minimum planning range of 2.5–3 litres per person per day.
It also explains that having around 10 litres per person per day provides greater capacity for basic cooking and hygiene.
These are different planning levels: drinking water alone is not the same as your household’s total water needs.
How much emergency drinking water should you store?
For straightforward household planning, use 3 litres per person per day as your initial drinking-water calculation.
For straightforward household planning, using 3 litres per person per day gives you a simple starting point for drinking water.
1 person
1 day: 3 litres
3 days: 9 litres
2 people
1 day: 6 litres
3 days: 18 litres
3 people
1 day: 9 litres
3 days: 27 litres
4 people
1 day: 12 litres
3 days: 36 litres
5 people
1 day: 15 litres
3 days: 45 litres
That is equivalent to twenty-four 1.5-litre bottles.
This is a planning calculation, not a guarantee that the same quantity will suit every household.
What about cooking and washing?
Drinking water is only part of the picture.
Think about the additional water your household might need for:
Preparing food and drinks.
Basic personal hygiene.
Cleaning essential items.
Caring for babies or young children.
Pets and other dependants.
Using the Government’s broader planning figure of around 10 litres per person per day, a four-person household would need approximately 40 litres daily, or 120 litres across three days.
You do not necessarily need to purchase everything immediately. Start with drinking water and gradually improve your household’s arrangements.
Calculate your household’s emergency water needs
Use this simple formula:
Number of people × daily water allowance × number of days
For example:
4 people × 3 litres × 3 days = 36 litres of drinking water.
Remember to account separately for pets and anyone with additional requirements.
Is water your household’s biggest preparedness gap?
Water is only one part of keeping your home functioning during disruption.
Take the free HomeStrength Home Check to review your preparedness across five areas:
Prepare · Power · Water · Connect · Protect
What is the best way to store emergency water?
You don’t need specialist survival equipment to get started.
For most households, sealed commercially bottled drinking water is a straightforward option.
A few practical considerations:
Store bottles somewhere cool, clean and away from direct sunlight.
Follow the manufacturer’s storage and date instructions.
Check your supplies periodically.
Rotate stored water into normal household use where appropriate.
Avoid storing containers where leaks could damage your property.
If filling your own containers, use suitable food-grade containers and follow appropriate cleaning and water-storage guidance.
It is also worth considering where you would access your supplies if part of your home became inaccessible.
What if your household includes children or pets?
A simple per-person calculation is only a starting point.
Your household may need additional water for infant feeding, specific dietary or medical requirements, pets, and basic cleaning.
Think about these requirements before an emergency rather than trying to improvise when your normal water supply is unavailable.
If you depend on particular medical equipment or have additional support needs, check whether you qualify for your utility provider’s Priority Services Register.
What should you do during an actual water outage?
First, check your water supplier’s website or emergency updates.
Follow any official advice about whether your tap water is safe to drink, whether boiling is required, or whether an alternative supply is being provided.
Do not assume that boiling makes water safe in every situation; it does not remove every possible contaminant.
Your water supplier’s specific instructions should take priority over general preparedness advice.
Start small. Build a more resilient household.
You don’t need to purchase a large emergency water supply in one shopping trip.
Start by calculating your household’s drinking-water requirements. Check what you already have, identify any additional needs and gradually build a sensible reserve.
Then consider the other things your household would need if normal services were disrupted.
For a wider overview, read our guide: UK Emergency Kit 2026: What Households Actually Need.
Get your household emergency plan organised
The HomeStrength Household Preparedness Pack brings your planning together in one printable workbook.
It includes:
Emergency food and water planning worksheets.
Household emergency contact templates.
Power-cut preparation.
Family grab-bag checklist.
Essential supplies tracker.
Seven-day action plan.
£9.99 · One-off purchase · Instant digital download
HomeStrength provides general household preparedness information. Always follow current advice from your water supplier and relevant emergency services during an actual incident.
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