In an emergency like a water main break, hurricane, or flood, it may not be safe to use the water. In such cases, it is important to know what to do to prevent certain illnesses from the bad water at home.
If you know or suspect that your water at home is contaminated, don’t use that water for drinking, cooking, washing dishes, or brushing your teeth. However, to make the water safe for drinking, cooking, and personal hygiene, you should boil, disinfect, or filter it.
If you don’t have safe or bottled water, the next best thing to do is boil the water and make it safe to drink. Boiling is the safest method to kill disease-causing germs, including viruses, bacteria, and parasites.
You can improve the taste of boiled water by pouring it from one container to another, then letting it stand for a few hours, or by adding a pinch of salt for each liter of boiled water.
In addition, there are a few steps you need to go through to boil the water:
- Boil the water for 3 minutes.
- Let the boiled water cool.
- Store the boiled water in sanitized containers.
When you don’t have bottled water and boiling the bad water is impossible, you can make small quantities of water safe to drink by using chemicals such as unscented household chlorine bleach, iodine, or chlorine dioxide tablets.
Disinfectants can kill harmful or disease-causing viruses and bacteria. However, most disinfectants are not as effective as boiling for killing more resistant germs such as Cryptosporidium and Giardia.
To disinfect the water with bleach, you should follow these steps:
- Read the instructions on the bleach label for disinfecting drinking water.
- If the label doesn’t have instructions, check the ingredients on the label to find the sodium hypochlorite percentage. Then add the appropriate amount of bleach using a medicine dropper, teaspoon, or metric measure (millimeters).
For 1 quart or liter you will need: 2 drops of bleach ( if you have a dropper)
0.1 ml bleach ( if using a metric scale)
A tiny amount (if using a measuring spoon).
- Stir the mixture.
- Let it sit for at least 30 minutes before using it.
- Store the disinfected water in sanitized containers.
Another option to have clean drinking water is using chemical tablets. These tablets are used often by campers and hikers. They are available in different sizes and are made to treat specific amounts of water. Therefore, to treat the water, you need to follow the instructions on the label or package.
Chlorine dioxide tablets can kill all kinds of germs, including Cryptosporidium, if you follow the manufacturer’s instructions correctly. However, iodine tablets kill most germs but not Cryptosporidium. Moreover, water that has been treated with iodine is not recommended for pregnant women, people with thyroid problems, or people who are known to have hypersensitivity to iodine.
Many portable water filters can kill disease-causing bacteria and parasites such as Cryptosporidium and Giardia from drinking water. The most effective way to make the water safe is to use a reverse osmosis water filter, as it removes 98% of dissolved solids, which makes it healthier to drink. Reverse osmosis removes contaminants from unfiltered water or feeds water with a pre-filter before it forces water through a semipermeable membrane to remove dissolved solids.
Every reverse osmosis water system carries a sediment filter and a carbon filter in addition to the RO membrane. The filters are either called pre-filters or post-filters depending on whether water passes through them before or after it passes through the membrane.
Photo by: “Fresh Water Systems” webpage
Each type of system contains one or more of the following filters:
- Sediment filters reduce particles such as dirt, dust, and rust.
- Carbon filters decrease volatile organic compounds (VOCs), chlorine, and other contaminants that give water a bad taste or odor.
- Semi-permeable membrane reduces total dissolved solids (TDS) by up to 98%.
Reverse osmosis systems usually last between 10 to 15 years. However, the prefilters and postfilters should be changed every six months to one year. Furthermore, the RO membrane should also be replaced every two to four years, depending on your water conditions.
Reverse osmosis may remove some bacteria, but bacteria could grow on the membrane and potentially enter the water supply.
Ultraviolet Light (UV Light):
- UV light can be used to eliminate some germs.
- Portable units that deliver a certain dose of UV light help disinfect small amounts of clear water. Moreover, the UV light doesn’t work well on cloudy water because small particles may block germs from the UV light.
- If the water is cloudy, you should filter it through a clean cloth, paper towel, or coffee filter, then draw off the clear water and disinfect it using UV light.
In emergencies, the sun’s rays can improve the quality of water, as it may reduce some germs in the water.
To disinfect the water using the sun, you should:
- Fill clean and clear plastic bottles with clear water since solar disinfection is not as effective on cloudy water because small particles may block germs from the light.
- If the water is cloudy, you should filter it through a clean cloth, paper towel, or coffee filter, then draw off the clear water and disinfect it using the sun.
- Lay the bottles down on their side and let them sit in the sun for six hours.
- Putting the bottles on a dark surface will help the sun rays disinfect the water more as the black color attracts sun rays.
In emergencies where your water is contaminated, you have many options to make that water safe to drink, cook, or use for personal hygiene again. Some of the most effective ways are boiling, disinfecting with chemicals, and using filters. There are other additional methods using ultraviolet light and solar disinfection, but these may not be as effective as the others.