During an emergency, such as natural disasters that damage your home or your regional infrastructure, utilities such as power and water often suffer damage that can limit or block access to essential resources. When the safety and cleanliness of the tap water in your home cannot be trusted, safe drinking water is an absolute necessity. In this article, we will help you stay prepared by discussing how to ensure water quality during emergencies.

The first thing you need to know is how to identify suspect sources of water. Tap water that has become cloudy or murky must be considered suspect, and should not be consumed unless treated first to purify and filter the water. Likewise, any water that comes from an open-air cistern or catch basin should be treated before any use for cooking, preparing foods, or drinking.

If necessary, with the right filtration and purification resources, cloudy, murky, or suspect water can be used as an emergency water supply. Even water from the toilet tank (not the toilet itself, but the reservoir tank) or the bathtub can be considered emergency water sources if purified and filtered properly. Remember, the average adult can survive for weeks with little to no food, but can only last for about three days without water.

One of the best ways to ensure a source of clean and safe water is to have something in place before disaster strikes. This means either having a ready supply of safe water in storage, or having the means to produce safe water at hand. An emergency supply of water can consist of commercially-bottled water or tap water in a food-grade water storage container. Emergency water containers should be stored out of direct sunlight. Any non-commercially bottled or non-pre-sealed containers of water should have their water replaced every six months.

If you do not have a pre-existing supply of emergency water, or have run out of reliably safe water, there are several methods you can use to treat a water supply to make it safer for consumption.

  1. Boiling water. Boiling water should kill harmful bacteria, viruses, and parasites, but will not treat the water for contaminants such as metals, minerals, or particulates.
    1. If the water is cloudy, first try to filter out particulates by pouring it into a container through a clean cloth or coffee filter.
    2. Boil the filtered water from 1 to 3 minutes.
    3. Let the water cool naturally, and store if possible in a clean container with a cover.
  2. Chlorinating water. Chlorine bleach can be used to disinfect and sanitize water, provided it is done properly. Like boiling water, bleaching will treat the water for microbial contaminants, but will not treat the water for metals, minerals, or particulates.
    1. Do not use scented, color safe, or bleaches with added cleaners. Use a chlorine bleach that is stored at room temperature for less than one year.
    2. If the water is cloudy, first try to filter out particulates by pouring it into a container through a clean cloth or coffee filter.
    3. The amount of bleach to add to the water depends on the concentration strength of the bleach:
      • If using bleach whose active ingredient is 5.25% – 6% sodium hypochlorite, add 8 to 16 drops of bleach per gallon of water.
      • If using bleach whose active ingredient is 8.25% sodium hypochlorite, add 6 drops of bleach per gallon of water.
    4. Stir the chlorinated water and let it sit for 30 minutes. There should be a slight chlorine odor. If not, repeat the dosage of bleach, stir, and let it sit for another 15 minutes.
    5. If a very strong bleach odor is present from the water, pour the water from one clean container into another and let it sit for a few hours before use.
  3. Filtering water. Even without power, a mechanical filtration method can be used to treat the water. This method can be used in conjunction with boiling or chlorinating the water. Filtering the water involves forcing the water through a filtration medium to trap any contaminants and remove them from the outflowing water. A Multipure Water Emergency Treatment (WET) System uses a carbon block filter, a bucket, and a siphon tube to pull source water from the bucket, through the filter, and out the tube. When used with water that has been boiled or chlorinated, the result is water that is generally safe for cooking, preparing food, and drinking.
  4. Bottled water. Bottled water can serve as an emergency water supply in that commercially-sealed, properly stored bottled water acts as a ready-made supply of safe drinking water. While it may be a valid solution for drinking water, its bulk and limited quantity renders it unlikely to be a valid source of water for cooking or preparing food. Unlike other methods of emergency water treatment, once the bottles of water run out, another method must be used to procure a safe supply of water.

When creating a supply of safe water, the goal is to store a minimum of 1 gallon of water per person per day, for 3 days. A 4-person household should have 12 gallons of safe water stored and ready for use. Ideally, you should store a 2-week supply of clean water, or 14 gallons per person, although this may not be feasible for all households.

The best method of ensuring water quality during emergencies is to use a multitude of the previous methods before and during the emergency. Having chlorine bleach and a Multipure Water Emergency Treatment (WET) system on hand allows you to treat most questionable sources of water for safe consumption. Having commercially-bottled water or stored containers of tap water as an emergency supply affords you an immediate source of safe water when needed, and gives you time to prepare additional safe sources of water through boiling, chlorinating, and filtering. Having clean, sealable food-grade containers allows you to treat and store water before, during, and after emergencies. Of course, knowing to examine and question the safety of your water source during an emergency allows you to identify and treat the water before anyone risks the consequences of potentially contaminated water. With the right knowledge and preparation, everyone can ensure a safer supply of water during an .




  1. “Water.” Ready.gov. February 22, 2021. https://www.ready.gov/water
  2. “Creating and Storing an Emergency Water Supply.” Centers for Disease Control and Prevention. January 26, 2021. https://www.cdc.gov/healthywater/emergency/creating-storing-emergency-water-supply.html
  3. “Emergency Disinfection of Drinking Water.” United States Environmental Protection Agency. Last accessed September 14, 2021. https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water