Drinking Water — Supplies & Treatment

How much you need

• 2 litres per person per day to drink + ~1–2 L for cooking/hygiene
• Recommendation in Germany (federal civil-protection office BBK): supplies for 10 days → approx. 20 L per person (minimum). Other countries have partly different recommendations — check the official civil-protection authority of your country (see the region box at the top).
• Pets: allow ~0.5–1 L/day depending on size
• Example: household with 2 adults + 1 dog (20 kg) → at least approx. 50 L of drinking water (2 × 20 L + ~10 L for the dog) + water for washing/flushing (bathtub trick). The supplies calculator (VORRAT.html) works it out for your own household.

Immediate action if an outage is imminent

While the water is still running: fill the bathtub, buckets, pots and bottles. Bathtub water = service water (toilet, washing), bottles = drinking water.

Water sources in the house (emergency)

• Hot-water tank (drain valve at the bottom) — switch off electricity/gas first
• Toilet cistern (only the cistern, never the bowl) — boiled only, and not if cleaning tablets are used
• Ice cubes in the freezer

Water treatment — in order of preference

1. Boiling (best method)

Bring to a rolling boil for at least 3 minutes. Kills bacteria, viruses, parasites. Does NOT remove chemicals/heavy metals.

2. Filtering

• Outdoor water filter (hollow fibre, e.g. 0.1 µm): bacteria & parasites yes, viruses usually not → then also boil or treat chemically
• Improvised pre-filtering (only removes cloudiness!): coffee filter, cloth, layers of sand, gravel and charcoal → ALWAYS boil afterwards

3. Chemical

• Water purification tablets (e.g. Micropur): follow the instructions on the pack, observe the contact time
• Household bleach (sodium hypochlorite 5 %, unscented): 2 drops per litre of clear water, wait 30 min. If it smells slightly of chlorine, it's OK. Double the dose for cloudy water. Only as a last resort.

4. UV/sunlight (SODIS)

Clear PET bottle, full sun, at least 6 hours (cloudy: 2 days). Only for clear water.

Never drink

• Water from radiators/the heating system (chemicals)
• Salt water, water from car batteries/windscreen washer systems
• Stagnant water that is discoloured/smells — if chemical contamination is suspected, not even after boiling

Storage

• Cool, dark, in food-grade containers
• Factory-sealed bottled water: keeps practically indefinitely (the best-before date is a formality; check smell/taste)
• Tap water you bottled yourself: replace after ~6 months or boil before use

Rainwater

Can be collected (clean surface, not the first few minutes of rain); filter + boil before drinking.