A disaster can both disrupt the electricity needed to pump water in to your home and contaminate the water supply. Plan ahead to be sure you have enough safe water for drinking, making food, brushing teeth, and keeping clean.

Storing Water

You can store water ahead for use in emergencies. Boiled water stored in sterilized containers will keep for six months to one year. While the water may taste flat, it is safe to drink or use in cooking.

Water From the Hot Water Heater

Your hot water heater or water pressure tank could supply many gallons of safe water during an emergency. Before using water from the water heater, switch off the gas or electricity that heats the water. Leaving the power on while the heater is empty could cause an explosion or burn out the elements. After turning off the power source, open the drain valve at the bottom of the tank. Do not turn the water heater on again until the water system is back in service.

If your well has been flooded or surface water has entered your well, the water needs to be treated with shot clorination. (See University of Maine Cooperative Extension bulletin #7115, Bacteria in Water Supplies, Part 2: How to Disinfect Your Well.)

Boiled water stored in sterilized containers will keep for six months to one year.

Disinfecting Water

Unless you are absolutely certain your water supply is not contaminated, purify all water before using it for drinking, preparing food, brushing teeth, or washing dishes. If the water contains sediment or floating material, strain it through a cloth before purifying it. If you have access to heat or power, water can be made safe by boiling. If not, you will have to treat it with chemicals.

Boiling (preferred method): Boil water at a rolling boil for 10 minutes to kill any disease-causing bacteria.

Chemical treatment: If you can’t boil water, chemical treatment will kill most disease-causing organisms. Any of the following three chemical treatments will purify water.

Chlorine bleach. Household bleach is a good disinfectant for water. Before using, check the label to be sure hypochlorite is the only active ingredient in the bleach. Do not use bleach that contains soap. Since the amount of chlorine in bleach is variable, use the following table to determine the appropriate amount needed to purify water. Mix the bleach thoroughly in the water, and let it stand for 30 minutes. The water should have a slight chlorine odor. If it doesn't, repeat the dose and let the water stand for an additional 15 minutes.

Percent chlorine	Add per gallon water
1%	40 drops
2 to 6%	8 drops
7 to10%	4 drops

Iodine. Household iodine from the medicine cabinet will purify water. The iodine should be 2 percent United States Pharmacopeia (U.S.P.) strength. Add 20 drops per gallon of clear water and 40 drops per gallon of cloudy water.

Water purification tablets. Water purification tablets will also purify water. These tablets are available at drug stores. Follow the manufacturer's instructions.

Return to Emergency Response Fact Sheets table of contents

Source: "Be Prepared with a 3-Day Emergency Food Supply," by E. Schafer, C. Hans, E. Jones Beavers and D. Nelson, Iowa State University Cooperative Extension, November, 1997. Reviewed by John Jemison, Extension water quality specialist.

For more information on emergency preparedness, contact your county UMaine Extension office.

©1998
Published and distributed in furtherance of Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.