A simple formula for emergency water, storage tips, and the safe ways to treat water you did not store.
- Formula: people and pets x days x 4 litres.
- Canadian guidance is at least 2 L per person per day for drinking alone.
- Filters do not remove every contaminant, so check what yours is rated for.
How much you need
Canadian guidance says at least 2 litres of drinking water per person per day. Cooking, brushing teeth and basic washing push the realistic number higher, so we use 4 litres as a planning figure. Hot weather, illness, nursing and small children all increase needs.
| Household | 3 days | 7 days |
|---|---|---|
| 1 person | 12 L | 28 L |
| 2 people | 24 L | 56 L |
| 4 people | 48 L | 112 L |
Storing it
- Use clean food-grade containers with tight lids. Used juice or milk jugs are hard to clean fully, so avoid them.
- Store in a cool, dark place. Label with the date.
- Replace stored tap water about once a year, or follow the container maker's advice.
- Your water heater tank holds a lot of water. Know how to drain it before you need it.
If you run out: treating water
Treatment depends on the source and the contaminant, so follow your health authority's steps. Health Canada and the CDC both publish them. The main options are:
- Boiling: a rolling boil kills germs. Health authorities give the exact time, so check before relying on it.
- Filters: gravity filters, pump filters and straw filters remove different things. Check what the filter is certified to remove.
- Chemical treatment: tablets or properly measured unscented bleach, only following official instructions.
Gear worth a look
These are common choices. Check the maker's page for current certifications, prices and availability.
Quick comparison
| Brand | Best for |
|---|---|
| BBerkey | Countertop gravity filter systems |
| LLifeStraw | Portable filters for backup and travel |
| FFrizzlife | Home countertop and under-sink filters |
Gravity-fed countertop filter. Needs no power, suits households.
- Gravity-fed, no pump needed
- Check which contaminants each model is rated for
- Plan how you will refill and clean it
Light personal filters for a grab bag or a car kit.
- Straw, bottle and larger formats
- Handy as a backup, not your main supply
- Check exactly what each model removes
Under sink and countertop filters for everyday use.
- Systems for daily home use
- Compare certifications and filter life
- Check replacement cost
Quick answers
Is tap water safe to store?
Treated municipal tap water in clean food-grade containers is a common choice. Replace it about once a year, or as the container maker advises.
Can I rely on a filter alone?
Not if flood water or chemical spills are possible. Most portable filters do not remove chemicals, heavy metals or salt.