In a disaster, water supplies may be cut off or contaminated. Store enough water for everyone in your family to last for at least three days. Store three litres of water, per person, per day. This amount will be adequate for general drinking purposes. Nine litres per person per day will give you enough to cook and for limited personal hygiene. Do not forget to plan for your pets.
Storing tap water
Store water in food-grade plastic containers, such as clean 2-litre soft drink bottles. Heavy duty, reusable plastic water containers are also available at sporting goods stores. Replace water at least once every six months (eg at daylight saving changeover times).
Not all bleaches are safe to use in stored drinking water
The Ministry of Civil Defence & Emergency Management has reviewed its advice about storing water for emergencies and has issued new, additional information.
The Ministry’s advice has been to add household bleach to stored water. That should still be done. However, with new products coming onto the market not all bleaches are safe to use in drinking water.
It is not safe to use bleaches that contain added scent or perfume, surfactants or other additives - they can make people sick. Surfactants will make the water foam or bubble when it is shaken or mixed. If the product's label is not clear about what has been added to the bleach, do not use the product for the safe storage of water.
Instructions for safely storing water
- Wash bottles thoroughly in hot water.
- Fill each bottle with tap water until it overflows.
- Add five drops of plain, household bleach per litre of water (or half a teaspoon for 10 litres) and put in storage. Do not drink for at least 30 minutes after disinfecting.
- Do not use bleaches that contain added scent or perfume, surfactants or other additives - they can make people sick.
- Label each bottle with dates showing when the bottles were filled and when they need to be refilled.
- Check the bottles every 12 months. If the water is not clear, throw it out and refill clean bottles with clean water and bleach.
- Store bottles away from direct sunlight in a cool dark place. Keep them in two separate places and where there is not likely to be flooding.
Storing commercially bottled spring or drinking water
- Keep water in its original container.
- Don't put a bottle back into storage once it has been opened.
- Label bottles with their replacement date and store in a cool, dark place.
- Replace water at least once every six months (eg at daylight saving changeover times).
Treating water after a 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). You cannot drink swimming pool or spa water, but you can use it for flushing toilets or washing.
Begin by straining any large particles of dirt by pouring the water through a couple of layers of paper towels or clean cloth. Next, purify the water using one of the following methods:
- boil - bring to a rolling boil and maintain for 3-5 minutes. To improve the taste, pour it back and forth between two clean containers to add oxygen back
- disinfect - if the water is clear, add 2-3 drops of bleach per litre. If it is cloudy, add 4-5. Shake or stir, then let stand 30 minutes. A slight chlorine taste and smell is normal.