Drinking water
How much to store, what it costs, and why the three official answers disagree.
Water is the first thing to fail and the cheapest thing to fix. A household can go a week without shops and barely notice. It cannot go two days without water.
It is also the category where official advice is least consistent. Germany, Austria and Switzerland each publish a figure, and the three do not match — not because anyone is wrong, but because they are measuring different things. Knowing which is which is most of the work.
The three official numbers
| Authority | Per person per day | For how long | Total per person |
|---|---|---|---|
| Germany — BBK | 2 litres, of which 0.5 l for cooking | 10 days (3 days as a minimum) | 20 litres |
| Austria — oesterreich.gv.at | 2.5 litres | 10–14 days | 35 litres |
| Switzerland — BWL | 3 litres | 3 days | 9 litres |
For context: the EU Preparedness Union Strategy of March 2025 asks member states to encourage households toward 72 hours of essential supplies. All three national figures sit at or above that floor, and Germany's sits more than three times above it.
Why they disagree
Switzerland's nine litres is the narrowest figure of the three and the most explicit about it. The federal brochure says the amount should cover drinking and cooking for three days, and states plainly that water for personal hygiene and flushing is not included.
Germany's two litres already contains half a litre of cooking water, so the drinking component is 1.5 litres. The BBK refines this elsewhere: people over 65 are counted at a full 2 litres of drinking water, children up to twelve at roughly 1 litre.
Austria is the only one of the three that puts a number on hygiene. Its guidance separates roughly 1.5 litres a day for drinking from around 3.5 litres to maintain a minimum of hygiene — which is why the Austrian total is the highest, and why it is the most honest about what a household actually consumes.
What we use. Two litres per person per day for drinking and cooking, held for fourteen days — 28 litres a person — with hygiene water handled separately rather than folded into the same bottles. That tracks the Austrian framing, which is both the most recently updated and the only one that accounts for the whole problem.
What to buy
Bottled mineral water, and carbonated in preference to still. The Austrian Zivilschutzverband recommends carbonated specifically for its longer shelf life; dissolved CO₂ suppresses microbial growth.
Shelf life follows the bottle, not the water. Germany's Federal Office for Agriculture and Food gives a best-before date of roughly two years for glass and one year for PET — PET is permeable enough that carbonation escapes through the wall over time. Sealed and stored properly, the water itself keeps far longer than either date. Store dark, cool and dry, and away from solvents, paint or fuel: PET is not an odour barrier.
At typical supermarket prices of €0.25 to €0.80 a litre, 28 litres costs between €10 and €20 per person. For most households this is the single cheapest resilience measure available, and it is the one most often skipped.
Storing tap water
Worth saying clearly: neither Germany nor Switzerland publishes household guidance on storing tap water, and that silence should not be read as a verdict either way. It simply is not covered.
In practice, tap water stores well in food-grade containers — the 10 and 20 litre canisters sold for camping. Fill them fresh, close them fully, keep them dark and cool, and replace the contents every six months. Treat stored tap water as a hygiene and cooking reserve rather than a drinking reserve unless you disinfect it, and do not use containers that previously held anything else.
Hygiene water, and the bathtub
Nobody stores 3.5 litres per person per day of washing water in bottles. For a family of four over two weeks that is nearly 200 litres.
The Austrian guidance names the obvious answer: a bathtub holds around 150 litres, and it recommends filling it early when there is any warning of an interruption — for example when mains water may exceed limits for a period. A bathtub is not a storage solution, it is a response, and it only works if you act before the pressure drops.
What is worth owning in advance is two 20-litre canisters and a bucket. That is roughly €25 to €40, it lives in a cupboard, and it turns "the taps are off" from a crisis into an inconvenience.
Making water drinkable
Of the three countries, only Austria publishes household water-treatment guidance. Germany's current guide covers disinfecting greywater and otherwise refers people to an outdoor retailer; Switzerland's federal material is silent. The three methods below are the ones Austria's Zivilschutzverband sets out.
Boiling. About one minute at a rolling boil. It is the most reliable method against bacteria, viruses and protozoa, and it needs a heat source that does not depend on mains electricity.
Chemical tablets. Silver- and chlorine-based tablets of the Micropur type both disinfect water and make it storable. The Austrian guidance puts the cost at under €20 for enough to treat 100 litres and recommends one pack per household as a standing item.
Solar disinfection (SODIS). A clear PET or glass bottle of 0.5 to 2.5 litres, filled three-quarters and shaken to oxygenate, then laid on its side in full sun for about six hours — roughly three days if it is overcast. The Austrian guidance, following WHO, puts the reduction in pathogens at 30 to 80 per cent, rising once the water passes 50 °C. It is a fallback, not a primary method.
What none of these do is remove chemical contamination, heavy metals or fuel. Disinfection is not purification. If water is cloudy, filter it first — Austria describes an improvised sand and charcoal filter for exactly this — and if it may be chemically contaminated, do not drink it at all.
A gravity or pump filter rated for bacteria and protozoa covers most European scenarios on its own; pair it with tablets if viruses are a concern. That is a purchase in the €40 to €150 range and it is the one item in this category worth spending real money on.
Rotating the stock
Austria anchors this to a date, which is the detail that makes it actually happen: the first Saturday in October, the day of the national siren test. One morning a year, check dates, drink down what is near expiry, replace it.
A stock you never rotate is a stock you discover is twelve years old at the moment you need it.
What a household should expect to spend
| Item | Approximate cost |
|---|---|
| 28 litres bottled water per person | €10–20 per person |
| Two 20-litre food-grade canisters and a bucket | €25–40 |
| Disinfection tablets, one pack | around €20 |
| Gravity or pump filter (optional, the serious version) | €40–150 |
A two-person household covers the first three lines for roughly €70 to €100 once, then about €20 a year to rotate. Against that, it is the only category where the consequence of being unprepared arrives within 48 hours.
Three things to do this week
1. Count what is in the flat right now, in litres. Most people are surprised in one direction or the other.
2. Buy the difference in one shop. 28 litres a person is roughly five six-packs for a couple.
3. Put the first Saturday in October in the calendar, repeating annually.
Sources. Germany: BBK, Bevorraten and BLE on storing mineral water. Austria: oesterreich.gv.at, Selbstschutz and the Zivilschutzverband guide. Switzerland: BWL, Kluger Rat — Notvorrat. Figures checked 31 October 2026.