How to Have Safe Drinking Water At Home

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During times of disaster and emergencies  like earthquake, typhoon, and flood, we must be ready with our water supply. The following guidelines must be observed to ensure that the water we drink is clean and safe.

Water Storage

We can purchase commercially bottled water in plastic containers. Avoid containers that are not made of polyethylene terephthalate plastic, commonly abbreviated as PET or PETE. Take note of the "best before" date so we know when to replace our stock. Almost every neighborhood has a water purification station and a 4-gallon container costs around 35 to 40 pesos. 

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If you choose to stock water yourself, consider the following:

• Use only food-grade containers. Smaller containers made of PET plastic or heavier plastic buckets or drums can be used also. Do not use containers previously used to store non-food products. 
• Clean, sanitize, and thoroughly rinse all containers before use. A sanitizing solution can be prepared by adding 1 teaspoon of liquid household chlorine bleach (5 to 6% sodium hypochlorite) to 1 liter of water. Do not use household bleach with thickeners or scents. 
• Label and put a date on the water container so you know when to cycle. Ideally, do not keep drinking water longer than 6 months. Supermarket supplied water needs to be cycled within 6 months to a year with fresh supplies.

Water Pretreatment

If water was obtained from a chlorinated water supply, there is no need for further treatment when stored in clean, food-grade containers. Non-chlorinated water should be treated with bleach  (5 to 6% sodium hypochlorite). Add 8 drops of liquid household chlorine bleach for every 4 liters (one gallon) of water. Use only household bleach without thickeners, scents, or additives. 

Storage

• It is recommended that you have a variety of containers of varying sizes so in case of home evacuation, everyone can possibly carry a water container.  
• Ensure that water containers are emptied and refilled regularly. 
• Store water only in areas where potential leakage would not damage your home.
• Store the water away from anything that could contaminate it such as pesticides, fungicides, insecticides, gasoline, paint, or any other chemicals.
• Protect stored water from light and heat. Use opaque containers.
• Fill the containers with water to overflowing and then place the lid on top. Don't leave an air gap. 
• Store water where it can be easily accessed.  

Water Purification

If your water supply is unsafe or has become contaminated, it should be purified before use. Generally, water purification consists of two-step process. 

Step 1: Clarify

Use filter paper, fine cloth, or some other filters to clarify cloudy or unclear water.  It should be allowed to settle and then the clear water on top can be carefully drawn then disinfected. 

Step 2: Disinfect

• Boiling Method. Boiling water for 3 to 5 minutes will kill most water-borne microorganisms. Do not prolong boiling of small quantities of water as it may concentrate toxic contaminants if present.
• Bleach Method. Adding 8 drops of fresh liquid household chlorine bleach (5 to 6% sodium hypochlorite) to every 4 liters (one gallon) of water will kill most microorganisms. Only household bleach without thickeners, scents, or additives should be used. It should be noted that the use of bleach does not address toxic contamination. 
• Commercial Water Filters. Commercial water filters can effectively filter and purify water contaminated with microorganisms, toxic chemicals, and heavy metals. Their effectiveness depends on design, condition, and proper use.

Sources:

Bradley, A.T. (2010). Handbook to Practical Disaster Preparedness.

Drinking Water Guidelines. https://www.lds.org/topics/food-storage/drinking-water-guidelines?lang=eng