Water and Sanitation in a Disaster

Water BackgroundAnother thing we take for granted is fresh water coming out of our taps and toilets that flush. Water and sanitation needs in a disaster are almost immediate.

Humans can live without food for 30 days or more if necessary. But we can only live for three days without water. In an emergency, people need at least one gallon of water per person, per day, for at least three days, for drinking and sanitation needs.

This problem is most easily solved by having enough water on hand in the house. In an extended emergency you may be able to treat the water (see below).

Water quickly becomes a precious resource following many disasters. Most of the time, the problem with water, is potential contamination from run off or sewage that overwhelms the waste water facilities. This can cause bacteria and other nasty stuff in the water making it non-drinkable. Cracked lines may also pollute the water supply to your house.

The effects of gravity may drain the water in your hot water heater and toilet tanks unless you trap it in your house by shutting off the main house valve (not the street valve in the cement box at the curb—this valve is extremely difficult to turn and requires a special tool). You may need to shut off your water until you hear from authorities that it is safe for drinking. All household members learn how to shut off the water at the main house valve.

Preparing to Shut Off Water

Locate the shut-off valve for the water line that enters your house. Make sure this valve can be completely shut off. Your valve may be rusted open, or it may only partially close. Replace it if necessary. Label this valve with a tag for easy identification, and make sure all household members know where it is located.

Water purification

There are two primary ways to treat water: boiling and adding bleach. If tap water is unsafe because of water contamination (from floods, streams or lakes), boiling is the best method. Cloudy water should be filtered before boiling or adding bleach. Filter water using coffee filters, paper towels, cheese cloth or a cotton plug in a funnel.

Boiling. The safest way to purify water is boiling. Bring the water to a rolling boil for one minute. Allow the water cool before drinking.

Bleach. Purifying by adding liquid chlorine bleach If boiling water is not possible, treat water by adding liquid household bleach, such as Clorox or Purex. Household bleach is typically between 5 percent and 6 percent chlorine. Avoid using bleaches that contain perfumes, dyes and other additives. Be sure to read the label to make sure it’s just bleach. Place the water (filtered, if necessary) in a clean container.

Ratio of Bleach to Water for Purification

  • 2 drops of Bleach per quart of water
  • 8 drops of Bleach per gallon of water
  • 1/2 teaspoon Bleach per five gallons of water

Mix thoroughly and allow water solution to rest for at least 30 minutes before using (60 minutes if the water is cloudy or very cold).

Sanitation during an Emergency

If the water lines are damaged e.g. an earthquake or landslide, do not flush the toilet. Avoid digging holes in the ground and using these. Untreated raw sewage can pollute fresh ground water supplies. It also attracts flies and promotes the spread of diseases. Even if water is available, local authorities may ask you not to use flush toilets, wash basins, and other fixtures connected with soil pipes.

The sewer mains may be broken or clogged, which would make it impossible to carry off such waste; or water may be needed for firefighting or other emergencies. Every family should know emergency methods of waste disposal in case such conditions arise.

Water flush toilets cannot be used when water service is interrupted. The water remaining in the fixture is not sufficient to flush the wastes down the sewer. Clogging may result and your living conditions then become just that much more uncomfortable.

Failure to properly dispose of human wastes can lead to epidemics of such diseases as typhoid, dysentery, and diarrhea. At the same time, sewage must be disposed of in ways that will prevent contamination of water supplies used for drinking, cooking, bathing, laundering, and other domestic purposes.

Here are simple steps that any family can take to prevent such dangers and discomforts. Store a large supply of heavy-duty plastic bags, twist ties, disinfectant, and toilet paper. An easy disinfectant is a solution of 1 part liquid bleach to 10 parts water. Dry bleach is caustic and not safe for this type of use.

If the toilet is NOT able to be flushed, it can still be used. This is less stressful for most people than using some other container. Remove all the bowl water and turn off the water line to the toilet. Line the toilet with a heavy-duty plastic bag. Portable camp toilets, small trash cans or sturdy buckets lined with heavy-duty plastic bags can also be used. Those with tight fitting lids are best.

When finished, add a small amount of diluted bleach solution, securely tie the bag, and dispose of it in a large trash can with a tight fitting lid. The trash receptacle should also be lined with a sturdy trash bag. Eventually, the city will provide a means to dispose of these bags.

Emergency and Disaster Planning

Disaster Kit

The Disaster

The Immediate Aftermath of a Disaster

Coping Emotionally with a Disaster

Disaster Assistance and Resources

Securing Valuable Information


American Red Cross

Be Prepared California

California Emergency Management Agency

Federal Emergency Management Agency

Kentucky Department of Public Health, Cabinet for Health and Family Services

Washington State Department of Public Health