How to Use Bleach to Purify Water for Drinking

Using Bleach to Purify Drinking Water

Lately, it feels like we’ve been inundated with tornadoes in the Midwest, out-of-season Hurricanes on the Coasts, and flooding in areas that are usually starved for rain. Using bleach to purify water for drinking is one skill that you absolutely need to know. It’s very easy to do, but there are a few things that you should know that could come back to bite you if you aren’t careful.

It’s easy to contemplate what it would be like to be left in a situation where electricity and water are no longer available. Above all, you and your family need to have access to clean drinking water. Knowing how to disinfect water is a valuable skill—one you should master so you never have to worry about dehydration.

Why Use Bleach?

Ideally, having the means to boil water as a means of decontamination is usually a consumer’s first line of defense. However, when utilities have been knocked out as a result of a natural disaster, your chances of having access to gas and electricity could negate this option.

Here are just a few reasons to keep a supply of bleach on hand:

  • It’s a standard household product used by homemakers for tasks that range from cleaning to disinfecting.
  • Bleach costs very little and is available by the gallon; both are reasons this product remains a household staple.
  • You can find bleach almost everywhere you shop: grocers, big-box stores, hardware stores and supermarkets.
  • Bleach can not only make water potable, but it can combat mold and mildew.

Does It Matter What Type of Bleach You Use?

It does. Though you may find various fragrances and extras, there are only two classifications of bleach: chlorine and non-chlorine.

If you are using bleach to disinfect water, you need to buy regular, unscented chlorine bleach with an active ingredient of between 6 and 8.25 percent of sodium hypochlorite. Does that mean you have to stop buying scented, color-safe and hybrid bleaches? Nope. Just buy both. One for your laundry uses, and one for prepper uses.

Clorox Regular Bleach – Unscented

I have had quite a few people contact me saying that they weren’t sure if they had the right type of bleach. So here is a link to it on Amazon.

This is regular, unscented bleach, with an 8.25% concentration of sodium hypochlorite. Make sure you also get some liquid droppers to dispense the correct amount of bleach into the water you are treating.

Using Bleach Concentrate

The question has come up many times as to whether or not you can use bleach that is labeled “concentrated bleach” to purify water. The answer is yes! Don’t read too much into the wording “concentrated.” Just read the bottle, most concentrated bleach is simply normal 8.25% chlorine (or sodium hypochlorite) bleach.

Bottles of Bleach Have Many Uses for Survivalists
Make sure you’re buying unscented, chlorinated bleach to purify your water.

How to Use Bleach to Purify Water

Having applied due diligence to your task of always keeping fresh chlorine bleach in your supply cabinet, it’s time to put all that you have learned to use by mixing up a batch of treated water. But don’t wait until you’re in the middle of a crisis. Undertake this experiment now, so you’ve got your technique down.

Before you start, gather the water you want to treat. This can be water from the tap, a river, a lake, a snowpack, rainfall you collected from your gutters or another source. Of course, the higher the quality the source, the better quality your water will be.

Step 1 – Add Bleach to the Water

Add either eight drops of 6 percent bleach or six drops of 8.25 percent bleach to one gallon of water.

Step 2 – Inspect and Adjust if Necessary

If that water is cloudy, colored, or very cold, experts recommend doubling the bleach to 12 or 16 drops respectively.

Step 3 – Wait

Allow the mix to stand for about 30 minutes.

Step 4 – Smell and Adjust if Necessary

Smell the solution. If you don’t detect a slight chlorine odor, add another 12 or 16 drops and let the water stand for 15 minutes more.

Step 5 – Reduce the Levels of Bleach in the Water

If the chlorine taste is off-putting when sampled, transfer containers. Allow the water to stand for several hours in the new container before you drink it (uncapped). You can also pour the water back and forth between two containers. This will help speed up the evaporation of the chlorine.

Mixing Larger Batches of Purified Water

If you are wanting to make larger batches of purified water, here are some ratios for larger quantities:

If you’re using 6 percent chlorine bleach:

  • 2 drops of bleach per quart or liter of water
  • 8 drops per gallon of water
  • 16 drops per 2 gallons of water
  • 1/3-teaspoon per 4 gallons of water
  • 2/3-teaspoon per 8 gallons of water

If you’re using 8.25 percent chlorine bleach:

  • 2 drops of bleach per quart or liter of water
  • 6 drops per gallon of water
  • 12 drops per 2 gallons of water
  • 1/4-teaspoon per 4 gallons of water
  • 1/2-teaspoon per 8 gallons of water
Using bleach to purify water - pouring between containers
Pouring the newly purified water between containers will slowly but surely remove that ‘swimming-pool’ taste and odor.

The Shelf Life of Bleach

Old bleach? Who knew that bleach had a shelf life? If you’re surprised to learn that bleach can expire, it’s a good thing you’re reading this.

According to the Clorox Company—the iconic brand that has been around forever—you need to track the age of your bleach. A company representative told Ron Fontaine, whose website offers tips on this broad category, “We recommend storing our bleach at room temperatures. It can be stored for about six months at temperatures between 50 and 70 degrees Fahrenheit.

After that time, bleach degrades at a rate of 20 percent annually until it’s nothing more than salt and water. Also, if you keep your bleach in a room that stays above 70 degrees (think dryer heat), it’s going to degrade even faster.

I cringe to think how many people have expired bleach in their disaster emergency kits for treating polluted water.” 

– Ron Fontaine (

Total Water Storage Type of Water Storage Solution Price Buy
Reliance Products Aqua-Tainer...image 7 Gallons Rigid Water Container (1 Pack) $15.92 See on Amazon
Cedilis 2 Pack...image 10.6 Gallons Collapsible Water Container with Spigot (2 Pack - 5.3 Gallon ) $21.59 See on Amazon
15 Gallon Emergency...image 15 Gallons Water Storage Barrel (1 Pack) $89.99 See on Amazon
Saratoga Farms 5-Gallon...image 30 Gallons Stackable Water Storage Containers with Lids (6 Pack - 5 Gallon) $190.00 See on Amazon
30 Gallon Stackable...image 60 Gallons Stackable Water Storage Tank (2 Pack - 30 Gallons) $380.00 See on Amazon

Tips for Storing Purified Water

Long-term water storage is a wise move that can pay dividends if a natural disaster strikes. The Centers for Disease Control and Prevention (CDC) is the resource we tapped into for advice in creating these nine purified water storage tips:

  1. Use only food-grade storage containers to hold your purified water.
  2. If you must use non-food-grade containers, get durable alternatives with caps that can be tightly closed.
  3. Never recycle old containers and fill them with water—especially if they have held toxic materials.
  4. If you’re uncertain about the origin, ask whether the container you’re considering is FDA-approved.
  5. Sanitize every container you plan to use. Mix one teaspoon of fragrance-free chlorine bleach with 1 gallon of water and pour it into the container. Shake vigorously. Let stand 30 seconds before you empty it and allow it to air dry.
  6. Slap a label on each container that’s marked “Drinking Water” and write in that day’s date.
  7. Store your containers out of direct sunlight in a cool environment that doesn’t exceed 70 degrees.
  8. Replace all water at 6-month intervals, after cleaning out the containers, to maintain freshness.
  9. Never keep your water supply near containers that hold gas, pesticides, or other toxins.

Other Uses for Bleach

Why suggest these activities when your mind is likely switching between panic and worry? Because if you’ve done your homework, you’ll be prepared to stay the course until things get back to normal and you’ll probably learn a lot about your ability to face adversity, too.

Use Bleach to Preserve Flowers

You can pick flowers while you wait for your power to be restored, says Dr. Joan Rose of the Water Quality and Health Council. Mix ¼-teaspoon of chlorine bleach per quart of water into the vase, and you’ll destroy the bacteria that makes them wilt.

Use Bleach to Sanitize

You can sanitize dishes and surfaces in your home using bleach. Really you can sanitize anything this way which might be especially useful in any kind of health epidemic. Sanitizing will become essential in any influenza or viral outbreak.

To sanitize using bleach, 1 teaspoon of bleach with about a cup of water. Dip a kitchen towel or rag into the mix, and wipe a surface thoroughly to disinfect. Then rinse before drying.

Use Bleach to Kill Mold and Mildew

Killing mold and mildew can be especially important if your home is without power for weeks or months. That is because without your home heating and air conditioning (HVAC) units running, air doesn’t circulate like it once did. Your home could grow mold and mildew much easier which can become a serious health hazard. This is especially true when spores get into the air you breathe. Luckily, household bleach can be used to kill these things.

To kill mold and mildew using bleach, mix one cup of bleach with one gallon of water. Soak the mold with this solution using either a rag or a spray bottle. Let the solution sit for at least 10 minutes before scrubbing the area clean. Wear eye protection, ventilate the area, and use a face mask to avoid breathing in any spores that are kicked into the air while cleaning.

An Environmental Protection Agency (EPA) Warning

According to EPA guidelines, when a crises strikes, only water that’s been “properly disinfected” should be used for drinking, cooking, washing dishes and tooth brushing. This is important to avoid disease-causing microorganisms that dwell in water supplies.

Among the solutions, the EPA suggests for purifying water are boiling and using a bleach additive to kill organisms that have the potential to make you and your family sick. That doesn’t mean that bleach is a perfect solution to your dilemma, however. Your water can still be laced with salts, heavy metals, and chemicals. Some of these are added by your water company; others find their way into your water thanks to Mother Nature.


Bleach really is the swiss army knife of chemicals for preppers. Unfortunately, you won’t be able to “store it and forget it” because it does have a shelf life. Bleach should be rotated just like most of your other preparations. Even so, you should always try to have usable bleach on hand. Trust me, when the next viral outbreak occurs, there will be no replacement for good old household bleach!

If you’re looking for other water-purifying methods, take a look at this list of the best methods for purifying water in survival situations.

John Walter

John Walter is an emergency preparedness consultant with eight years of experience and training in related fields. He is a passionate prepper living in the Sacramento area of California.

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