Drinking Water: What’s Safe and How to Make It Safer

Disaster Guide

Contents

  1. What Water Is Safe To Drink
  2. How To Make Water Safer
  3. Preventing Waterborne Diseases

This guide explains what water is safe to drink after a disaster and how to make unsafe water safer using boiling or solar methods. It also shows how to prevent waterborne diseases like diarrhoea and dehydration, which spread easily in crowded or low-resource settings.

Drinking unsafe water can cause serious illness. Use this guide to protect yourself and your family.

What Water Is Safe To Drink

After a disaster or emergency, tap water may not be safe to use.

  • Use bottled water for drinking, cooking, and brushing teeth if possible.
  • If bottled water is not available, choose one of the following methods to make your water safe.
​Water contaminated with harmful chemicals or toxins (e.g. pesticides, fuel, industrial waste) cannot be made safe by boiling, disinfecting, or filtering.

How To Make Water Safer

Boil (most effective method):

Boil your water to make it safe to drink:

  1. If the water is cloudy, first filter it through a clean cloth, paper towel, or coffee filter. Or let it settle and use only the clear water.
  2. Boil your water for at least 1 minute.
    1. Let the boiled water cool.
      1. Store the boiled water in clean, sanitised containers with tight covers.

      Solar Disinfection:

      The sun’s rays can improve the quality of your water by reducing the number of germs in it.

      1. If the water is cloudy, first filter it through a clean cloth, paper towel, or coffee filter. Or let it settle and use only the clear water.
      2. Fill clean, clear plastic bottles with clear water.
        1. Lay the bottles down on their side and in the sun for:
          • 6 hours (if sunny) 
          • 2 days (if cloudy). 

        Laying the bottles flat on a dark surface to help the sun's rays kill more germs.

        Preventing Waterborne Diseases

        Unsafe water can cause diarrhoea, vomiting, and dehydration and even death — especially dangerous for children and the elderly. 

        These illnesses spread fast in crowded shelters.

        Tips to stay safe:

        1. Drink Only Safe Water

        • Use bottled, boiled, disinfected or solar-treated water
        • Don’t drink water from unknown or dirty sources

        2. Wash Hands Often

        • Before eating or cooking
        • After using the toilet
        • Use soap and safe water, or hand sanitiser (60% alcohol)

        3. Keep Food Safe

        • Don’t eat food touched by floodwater
        • Throw out food that smells bad or has no refrigeration

        4. Proper sanitation

        • Keep toilets away from water sources
        • Don’t defecate near rivers or ponds

        5. Avoid Dirty Water

        • Don’t bathe in floodwater
        • If contact happens, wash with clean water right away

        Watch For Signs Of Dehydration

        Unsafe water can cause diarrhoea and dehydration, which can lead to serious illness or even death — especially in babies, young children, and older adults. Spotting symptoms early can save lives.

        Look out for:

        • Watery diarrhoea 3 or more times a day
        • Dry mouth, lips, or tongue
        • Sunken eyes or no tears when crying
        • Very little or dark urine
        • Feeling weak, dizzy, or confused

        If you notice any of these signs:

        Start giving oral rehydration solution (ORS) immediately and monitor the person closely.

        For more information about dehydration and when to get help, see the Dehydration First Aid Guide.

        To learn how to easily make and use Oral Rehydration Solution (ORS) yourself, go to the ORS Guide.

        Food Safety
        Disaster Guide