Sweden's Agency for Civil Defence (MCF) says an adult needs three to five litres of water per day, covering drinking, cooking and basic hygiene. Over seven days that is 21 to 35 litres per person, so a household of four needs roughly 84 to 140 litres. No consumer emergency kit contains that much water. The realistic answer is to store what you have room for and keep a reliable way to treat more. Here is how to work out the number for your own household, and how a container and a filter actually compare.
Reviewed by Oskar Björk, adviser and co-founder of Kapsel, defence engineer at the Swedish Armed Forces (Försvarsmakten). Last updated 2026-09-21.
How much water the official guidance actually says
MCF, Sweden's Agency for Civil Defence, asks every household to be able to manage at least one week on its own, and to plan for water, food, communication and heat across those seven days. Its figure for water is three to five litres per adult per day. That range is not only drinking water. It is meant to cover drinking, cooking and basic hygiene together, which is why it is higher than the three litres often quoted.
Two things follow from that. The first is that the weekly number per person is 21 to 35 litres, not 21. The second is that the total scales with the number of people in the home, and it scales fast.
Work out the number for your household
Multiply people by days by litres. At the low end of the range that is three litres per person per day, at the high end five.
| Household | 7 days at 3 litres a day | 7 days at 5 litres a day |
|---|---|---|
| 1 person | 21 litres | 35 litres |
| 2 people | 42 litres | 70 litres |
| 4 people | 84 litres | 140 litres |
| 6 people | 126 litres | 210 litres |
Write your own number down. It is the single most useful figure in your whole preparedness plan, because everything else in this article is measured against it.
What a water container actually covers
A container is stored water. It is ready the moment you need it, it needs no power, no heat and no technique, and anyone in the home can use it. Those are real advantages and they are the reason to own one.
The limit is arithmetic. A 30 litre container holds six to ten days for one person, which is genuinely enough for a single-person household. For a family of four the same 30 litres is one and a half to two and a half days. Double it to 60 litres and a family of four gets three to five days, still short of the week. To actually store a week for four people you need somewhere between 84 and 140 litres standing in your home, refreshed regularly, which is around four to seven full 20 litre jerry cans.
Stored water also has a shelf life in practice. Tap water in a clean, sealed, food-grade container kept dark and cool stays drinkable for a long time, but the container needs checking and the water needs rotating. A store you never look at is a store you cannot trust.
What a filter actually covers
A filter is not stored water. It is the ability to keep producing drinkable water for as long as there is a source, and that is a different kind of security. It weighs almost nothing, it does not expire the way a full container is rotated, and it does not take up a cupboard.
Its limit is the mirror image of the container's. A filter needs something to filter. In the most common Swedish scenarios there is water available but it is not safe to drink: a burst main, a boil-water notice, contamination after flooding, or a power cut that stops the treatment works. In those cases the tap still runs and a filter turns that into drinking water. In the rarer case where the supply stops entirely, a filter is only as good as the nearest lake, stream or collected rainwater you can reach.
A filter also does not do everything. Mechanical filtration removes bacteria and protozoa. It does not remove chemicals, fuel or heavy metals, which is why you always start from the clearest, least suspect source you can find. Our guide on how to purify water in an emergency covers boiling, tablets and filters, and when each one is the right tool.
The honest answer is both, in this order
- Store what you actually have room for. Not the full week if that is unrealistic in a flat, but a real, rotated store you know the volume of. Two 20 litre containers is a good, achievable target for most homes.
- Keep a way to treat more. A filter, purification tablets, and the ability to boil. This is what turns a two day store into a seven day plan.
- Know your sources. Where the nearest surface water is. Where your building's water comes from. Where the municipality would place an emergency water tank. Knowing this in advance costs nothing today.
Treat the container as the thing that carries you through the first days without any effort, and the filter as the thing that carries you through the rest. Neither one is the complete answer on its own, and a kit that sells you one as if it were the whole solution is telling you half the story.
What Kapsel includes, and what it does not
Kapsel Core is built for the treatment side, not the storage side, and we say so plainly. The system includes a filtered water bottle, a personal filtration straw and water purification tablets, so you have three independent ways to make water drinkable. It does not include stored drinking water, food or personal prescription medicines. Those are yours to add, because water is heavy, because your household size decides the volume, and because we would rather tell you the number than pretend a bag can contain it.
That is also why a full week of water is not something any kit at any price can put in a box for a family. The question to ask a supplier is not how many litres they ship you. It is whether they told you the real number you need, and gave you a dependable way to reach it.
Want the rest of the week sorted?
Water is the first thing to secure, not the only one. Kapsel Core covers cooking, warmth, light, communication, first aid and water treatment for seven days in one system, reviewed by a defence engineer and quality-checked in Borås.
See Kapsel CoreWhere this fits in your preparedness
Water is one of the basics, alongside heat, light, communication and food. Plan the amounts with our guide to food and water stores for a week, build the rest of the kit from the complete emergency-kit checklist, and read what happens to a household during a water shortage or irrigation ban. If the power goes at the same time, see how to get through a week without power and water. See the full range of complete emergency kits, or go straight to the Kapsel Core.
Frequently asked questions
How much water should I have at home in a crisis?
MCF's guidance is three to five litres per adult per day, covering drinking, cooking and basic hygiene. For seven days that is 21 to 35 litres per person, so a household of four needs roughly 84 to 140 litres.
Is a water container or a water filter better?
They solve different problems. A container gives you water that is ready with no effort, but a fixed amount that runs out. A filter gives you an unlimited amount as long as there is a source, but it needs a source. Most households should have a modest stored volume and a reliable way to treat more.
Is a 30 litre water container enough for a week?
For one person, yes, 30 litres covers six to ten days. For a household of four it covers one and a half to two and a half days, so it needs to be paired with a way to treat more water.
Does an emergency kit include drinking water?
Almost never in a meaningful amount, and you should be suspicious if one claims to. A week of water for a family weighs over a hundred kilos. Kapsel Core includes filtration and purification but not stored drinking water, which you add yourself.
How long can you store tap water at home?
Tap water in a clean, sealed, food-grade container kept dark and cool stays drinkable for a long time, but it should be checked and rotated rather than left and forgotten. If in doubt, treat it before drinking.
Can I just filter water from a lake or stream?
A mechanical filter removes bacteria and protozoa, so surface water is usable. It does not remove chemicals, fuel or heavy metals, so start from the clearest water you can find and avoid any source that may be chemically contaminated.
Sources: MCF, the Swedish Agency for Civil Defence, Livsmedelsverket on drinking water, and krisinformation.se on home preparedness.