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Making Water Safe in an Emergency

In an emergency, water contaminated with germs can often be made safe to drink by boiling, adding disinfectants, or filtering.

IMPORTANT: Water contaminated with fuel, toxic chemicals, or radioactive material will not be made safe by boiling or disinfection. Use bottled water or a different source of water if you know or suspect that your water might be contaminated with fuel or toxic chemicals.

In emergency situations, use bottled water if possible; bottled water is the safest choice for drinking and all other uses. If bottled water is not available, the following methods can help make your water safe to drink.  

*Note: These methods are listed in order of what is most effective at making your water safe.

1. Boiling

If you don’t have safe bottled water, you should boil your water to make it safe to drink. Boiling is the surest method to kill disease-causing organisms, including viruses, bacteria, and parasites.

You can improve the flat taste of boiled water by pouring it from one container to another and then allowing it to stand for a few hours; OR by adding a pinch of salt for each quart or liter of boiled water.

If the water is cloudy:

  1. Filter it through a clean cloth, paper towel, or coffee filter OR allow it to settle.
  2. Draw off the clear water.
  3. Bring the clear water to a rolling boil for 1 minute (at elevations above 6,500 feet, boil for three minutes).
  4. Let the boiled water cool.
  5. Store the boiled water in clean sanitized containers with tight covers.

If the water is clear:

  1. Bring the clear water to a rolling boil for 1 minute (at elevations above 6,500 feet, boil for three minutes).
  2. Let the boiled water cool.
  3. Store the boiled water in clean sanitized containers with tight covers.

2. Disinfectants

If you don’t have safe bottled water and if boiling is not possible, you often can make small quantities of filtered and settled water safer to drink by using a chemical disinfectant such as unscented household chlorine bleach.

Disinfectants can kill most harmful or disease-causing viruses and bacteria, but are not as effective in controlling more resistant organisms, such as the parasites Cryptosporidium and Giardia. Chlorine dioxide tablets can be effective against Cryptosporidium if the manufacturer’s instructions are followed correctly.

If the water is contaminated with a chemical or radioactive material, adding a disinfectant will not make it drinkable.
To disinfect water with unscented household liquid chlorine bleach:

To disinfect water with unscented household liquid chlorine bleach:

If the water is cloudy:

  1. Filter it through a clean cloth, paper towel, or coffee filter OR allow it to settle.
  2. Draw off the clear water.
  3. Follow the instructions for disinfecting drinking water that are written on the label of the bleach.
  4. If the necessary instructions are not given, check the “Active Ingredient” part of the label to find the sodium hypochlorite percentage; and use the information in the following table as a guide. Typically, unscented household liquid chlorine bleach in the United States will be between 5 and 9% sodium hypochlorite, though concentrations can be different in other countries. Using the table below, add the appropriate amount of bleach using a medicine dropper, teaspoon, or metric measure (milliliters).
  5. Stir the mixture well.
  6. Let it stand for at least 30 minutes before you use it for drinking.
  7. Store the disinfected water in clean, sanitized containers with tight covers.

If the water is clear:

  1. Follow the instructions for disinfecting drinking water that are written on the label of the bleach.
  2. If the necessary instructions are not given, check the “Active Ingredient” part of the label to find the sodium hypochlorite percentage; and use the information in the following table as a guide. Typically, unscented household liquid chlorine bleach in the United States will be between 5 and 9% sodium hypochlorite, though concentrations can be different in other countries. Using the table below, add the appropriate amount of bleach using a medicine dropper, teaspoon, or metric measure (milliliters).
  3. Stir the mixture well.
  4. Let it stand for at least 30 minutes before you use it for drinking.
  5. Store the disinfected water in clean, sanitized containers with tight covers.
Making water safe to use with bleach having a 5%-9% concentration of sodium hypochlorite (most common in the US). If the water is cloudy, murky, colored, or very cold, add double the amount of bleach listed below.
1 quart/liter water 1 gallon water 5 gallons water
If you have a dropper:
Add 2 drops of bleach
If you have a dropper:
Add 8 drops of bleach
If you have a dropper:
Add 40 drops of bleach
If you have something that measures milliliters (mL):
Add 0.1 mL of bleach
If you have something that measures milliliters (mL):
Add ½ mL of bleach
If you have something that measures milliliters (mL):
Add 2½ mL of bleach
If you have a measuring spoon:
Amount too small to measure
If you have a measuring spoon:
Add a little less than 1/8 teaspoon
If you have a measuring spoon:
Add ½ teaspoon of bleach

 

Making water safe to use with bleach having a 1% concentration of sodium hypochlorite (this concentration is not common in the US, but is used in other countries). If the water is cloudy, murky, colored, or very cold, add double the amount of bleach listed below.
1 quart/liter water 1 gallon water 5 gallons water
If you have a dropper:
Add 10 drops of bleach
If you have a dropper:
Add 40 drops of bleach
If you have a dropper:
Add 200 drops of bleach
If you have something that measures milliliters (ml):
Add ½ mL of bleach
If you have something that measures milliliters (ml):
Add 2½ mL of bleach
If you have something that measures milliliters (ml):
Add 12½ mL of bleach
If you have a measuring spoon:
Add ⅛ teaspoon of bleach
If you have a measuring spoon:
Add ½ teaspoon of bleach
If you have a measuring spoon:
Add 2½ teaspoons of bleach

Tablets can be used to disinfect water and are popular among campers and hikers, as well as in other countries. They are available in different sizes and made to treat specific amounts of water. To disinfect water with tablets:

  • Follow the manufacturer’s instructions on the label or in the package.
    • Chlorine dioxide tablets can be effective against Cryptosporidium if the manufacturer’s instructions are followed correctly.
    • Iodine and iodine-containing tablets (tetraglycine hydroperiodide) or chlorine tablets are not effective against CryptosporidiumWater that has been disinfected with iodine is NOT recommended for pregnant women, people with thyroid problems, those with known hypersensitivity to iodine, or for continuous use for more than a few weeks at a time.

3. Filters

Many portable water filters can remove disease-causing parasites such as Cryptosporidium and Giardia from drinking water.
If you are choosing a portable water filter:

  • Try to pick one that has a filter pore size small enough to remove parasites (such as Giardia and Cryptosporidium). Most portable water filters do not remove bacteria or viruses.
  • Carefully read and follow the manufacturer’s instructions for the water filter you intend to use.
  • After filtering, add a disinfectant such as iodine, chlorine, or chlorine dioxide to the filtered water to kill any viruses and remaining bacteria.

For more information about water filters that can remove parasites, contact us for more information.

Top 5 Types of Drinking Water Filters

Our guide to filtration types helps you make an educated decision about which water filter makes the most sense for your home.

By: Aditi Pai

Making choices is stressful, but sometimes a selection, like picking out a loaf in the bread aisle, can only steer you so wrong. While other times, for instance choosing a water filter for your home, the decision is critical.

No one wants to spend money on a water filter only to find out that the filter solves a problem they don’t even have. And yet, when faced with the multitude of water filtration options, it can feel intimidating to find the right one for your home – the one that not only makes your water taste great but also rids it of the maximum number of contaminants.

It’s incredibly important to diagnose the “problem,” or in this case, assess the existing quality of tap water before choosing a filter. Tap water varies by region and depending on its source could be treated for any number of contaminants.

Fear not. It is simpler than you think. Below is a breakdown of the most popular types of water filters on the market to help you make an educated decision about what water filters make the most sense for your home.

Before delving into the nitty-gritty, there’s one important fact to keep in mind: it’s incredibly important to diagnose the “problem,” or in this case, assess the existing quality of tap water before choosing a filter. Tap water varies by region and depending on its source could be treated for any number of contaminants. The Environmental Working Group (EWG) has a helpful resource for anyone looking to learn about his or her water, called the Tap Water Database. It’s a great place to get a basic understanding of local water quality.

Here’s a list of five popular water filtration types on the market.

ACTIVATED CARBON

Good for removal of chlorine, chloroform, agricultural chemicals, organic substances, sediment, and magnesium.

Activated CarbonThe key to understanding how activated carbon works is adsorption. As opposed to absorption, in which one material will take in or soak up another material, adsorption occurs when one material sticks to another while passing through. This is the basis of activated charcoal or activated carbon.

Activated charcoal is created when organic material with high carbon content (like wood, coal, or coconut shells) is heated in such a way that it does not burn, but instead results in char. The char is then treated to create a porous material that binds to certain toxins and impurities, thus pulling them out of the water flowing through the system.

This is the most common type of filter and often used in conjunction with other filtration methods for maximum toxin removal. Aquasana Whole House Filter Systems, for example, are activated carbon filtration systems that incorporate a salt-free water conditioner, copper-zinc and mineral stone, and UV for maximum filtration.

ION EXCHANGE

Good for removal of hard water and radioactive material.Ion Exchange

As the name suggests, ion exchange filters consist of a substance that will exchange one ion for another as water flows through it. For example, ion exchange will replace calcium or magnesium ions, which cause water hardness, with sodium ions. This will “soften” the water. A home may be experiencing hard water if its water leaves stains on washed dishes. Hard water tends to build up in pipes, which may decrease the life of certain kitchen appliances.

Although ion exchange helps with hard water and some radioactive material, the filter does not remove organic material, particles, or bacteria as effectively as other filtration options.

REVERSE OSMOSIS (RO)

Good for effective removal of a high percentage of toxins including fluoride, hexavalent chromium, arsenic, nitrates/nitrites, copper, radium, salt, and more.

Reverse OsmosisTalk about a good bang for your buck – reverse osmosis filters are incredibly popular for a very good reason. Reverse osmosis filters are top of the line for removing a large percentage of contaminants out of the water, potentially including dangerous waterborne bacteria.

The filters work by pushing water through the reverse osmosis membrane using pressure. The contaminants remain on one side of the film while fresh water is pushed to the other side. It’s one of the few filters that can rid water of water-soluble contaminants like fluoride and chromium +6. If a home has a water softener, an RO system will also remove the salt from drinking water.

While these are becoming a popular option, reverse osmosis systems use an inordinate amount of water – sometimes up to four times the normal amount. The process is also slow, causing a decrease in water pressure. That’s why whole home reverse osmosis systems typically don’t exist. Further, the level of filtration isn’t necessary for day-to-day activities like flushing toilets, taking showers, and doing dishes. Learn more about the pros and cons of RO here.

MECHANICALMechanical

Good for removal of physical particles and waste matter.

Mechanical filters are most often used as a pre-filtration method. Water flows through a mechanical filter and waste material will get stuck between nylon floss, synthetic foam, or in pads. For example, in the case of a fish tank, the filter will trap plant materials, leftover fish food, and waste without trapping beneficial bacteria that is good for fish.

ULTRA VIOLET FILTERS

UV_FilterGood for the removal of bacteria and viruses.

An environmentally friendly option, UV filters will clean water using different frequencies of ultraviolet light.

The DNA in microbial cells absorbs this UV light, which essentially kills all bacteria and viruses, thus sanitizing drinking water. It’s important to note that UV filters only rid water of bacteria and viruses so it’s important to use this filter in conjunction with other types of filters to remove prevalent contaminants like chlorine, lead, and pesticides, leaving you with clean, drinkable water.

Contact us for more information.