In a disaster, water supplies may be cut off or contaminated. Store enough water for everyone in your family to last for at least 3 days.
- Store one gallon of water per person, per day. Three gallons per person per day will give you enough to drink and for limited cooking and personal hygiene. Remember to plan for pets.
If you store tap water:
- Tap water from a municipal water system can be safely stored without additional treatment.
- Store water in food grade plastic containers, such as clean 2-liter soft drink bottles. Heavy duty, reusable plastic water containers are also available at sporting goods stores. Empty milk bottles are not recommended because their lids do not seal well and bottles may develop leaks.
- Label and store in a cool, dark place.
- Replace water at least once every six months.
If you buy commercially bottled “spring” or “drinking” water:
- Keep water in its original container, and don’t re-store a bottle once it’s been opened.
- Store in a cool, dark place.
- If bottles are not marked with the manufacturer’s expiration date, label with the date and replace bottles at least once per year.
Treating Water after Disaster:
If you run out of stored drinking water, strain and treat water from your water heater or the toilet reservoir tank (except if you use toilet tank cleaners). Swimming pool or spa water should not be consumed but you can use it for flushing toilets or washing.
Strain any large particles of dirt by pouring the water through layers of paper towels or clean cloth. Next, purify the water one of two ways:
- Boil – bring to a rolling boil and maintain for 3-5 minutes. After the water cools, pour it back and forth between two clean containers to add oxygen back; this will improve its taste.
- Disinfect – If the water is clear, add 8 drops (1/8 teaspoon) of bleach per gallon of water. If it is cloudy, add 16 drops (1/4 teaspoon) per gallon. Make sure you are using regular bleach— 5.25% percent sodium hypochlorite— rather than the “ultra” or “color safe” bleaches. Shake or stir, then let stand 30 minutes. A slight chlorine taste and smell is normal.
San Francisco Public Utilities Commission: www.sfwater.org or call 3-1-1.