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There are many ways you can purify water. But does freezing water kill bacteria? No! Effective ways to kill bacteria are through the best water ionizers or reverse osmosis systems.

It’s a common misconception to freeze water kills contaminants. The method can help slow down bacteria build-up but doesn’t permanently eliminate them. Let’s do a rundown on why freezing water won’t kill bacteria and how you can purify it.

Does freezing tap water purify it?

Freezing and chilling can help slow down bacteria from growing but not necessarily kill them. It’s great for storage but never an option for purifying or sanitizing water. Whatever contaminants and bacteria in your tap water can still linger after defrosting. 

While the U.S. Department of Agriculture (USDA) says that freezing can kill parasites, they still note that a sub-zero freezing temperature can only achieve this. Plus, counting on home freezing to kill parasites is not recommended.

Deadly parasites like Cryptosporidium Oocysts can be in public surface water sources. But the Virginia Department of Health noted that the EPA implemented the Long Term 2 Enhanced Surface Water Treatment Rule (LT2) that systems with surface water surfaces should monitor their supply for oocysts. 

One way to remove Cryptosporidium Oocysts is to heat your water to a rolling boil for 1 minute, killing most impurities. Rolling boil pertains to water being so hot that it is past the boiling point.

If you are unsure about your water’s cleanliness, especially after an emergency or disaster, refrain from using your water for drinking, cooking, especially making ice. 

Is ice from tap water safe?

Standards for water cleanliness may depend on the area. Though public water systems in the U.S. are required to be drinkable, traces of chemicals for purifying, like Chlorine, can still be found.

Additionally, the CDC advises avoiding well or tap water for making ice and drinks like juice or milk. The best option is to purify your water before drinking or using your water.

Does freezing water remove chlorine?

Chlorine and other chemicals can survive freezing. It is a stable and soluble chemical that can stay in the water even when frozen. Water Technology shares filtering or purifying your water is best to remove chlorine before making ice.

Here are a few methods for removing chlorine from your drinking water according to Sciencing:

  1. The air evaporation process: Let your water sit for a long time for the chlorine to evaporate. Use a large-mouthed container to let the water’s surface be more exposed to air to evaporate the chlorine. However, this method only removes chlorine.
  2. Boil water to a rolling boil point: Heating water to a rolling boil point for at least 20 minutes can remove various impurities like chlorine. Boiling can speed up the process of evaporating it.
  3. Activated carbon filters: Activated carbon filters can absorb and kill chemicals like chlorine You can use these in water filtration systems like reverse osmosis or water ionizers.
  4. Chemical treatment: Chemical disinfectants like tablets and additives like chlorine dioxide can help odors, tastes, and microbes. It’s a popular technique used for camping, hiking, and other countries. But, this will only be effective by following the correct instructions from the manufacturer. Sciencing also recommended alternatives like vitamin C which are more edible.
    On the other hand, CDC suggested Iodine; this, however, is unsafe for pregnant women and patients with thyroid problems. Using chemical treatment should be done under the advice of a professional and can be dangerous when done wrong.

Does freezing tap water kill germs?

Like parasites and other impurities, germs become inactive and slow down from spreading when frozen, but that does not kill them. Using unpurified iced tap water for cooking and drinking can lead to infection and food poisoning.

Freezing food and water can preserve germs and other harmful bacteria than kill them. Once the ice melts, contaminants become active again, leaving you vulnerable to infections. However, modern and traditional methods to get rid of bacteria are available. After purifying water, you can then freeze it.

3 Ways to purify water at home

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Unlike freezing, there are other ways to successfully remove impurities like diseases, bacteria, metals, and parasites. Freezing temperatures are meant to store while purifying is more than that. Here are some of the best methods of purifying water: 

Water Ionizer

Water ionizers are powerful with filtration systems and electrolytes to remove pollutants and life matter. It uses platinum-covered electrodes to produce ions to adjust your water’s ph levels, making purified acidic and alkaline water depending on your needs. 

Reverse Osmosis Filtration System 

Filtration systems with a reverse osmosis system can separate and remove finer impurities that most filtration tank systems cannot do. Its passage type for water is stricter at a pore size of 0.0001 microns, blocking away more contaminants. 

Other models now also provide mineralization and extra UV disinfection. It also uses activated carbon filters to remove chlorine and odors from your water.

Water Distiller 

Distiller Machines boil water to high temperatures to create steam. The steam later converts back and becomes purified water having all impurities and chemicals killed. It supplies soft water for drinking, baby formula, sterilization, and medical supplies. 

The only downside is its metallic taste and lack of healthy minerals. Some distiller machines also use activated carbon filters to help kill volatile organic compounds (VOCs) and chlorine for healthier pure water.

Does boiling tap water purify it?

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Definitely! Boiling water can kill all contaminants in your water; it is one of the most traditional and convenient ways of purifying, especially during emergencies. The most trustworthy source of purified water is to boil tap water if your filtration system is not working and your area has undergone a disaster as water systems are down, leaving you more exposed to contaminated water.

Hot water kills germs, though it has to be very hot

Boiling water is a known way to help kill germs, but it needs to be heated at high temperatures to remove bacteria and other pollutants effectively. UPMC Health Beat notes that most organisms die when the water has reached a temperature of 212F boiling point, and no organism can survive for longer than 30 minutes in water at a temperature of 160F. 

Here are 3 easy steps to boiling water: 

  1. Set the pot to a rolling boil temperature of 212F (at an elevation above 6500 ft).
  2. Proceed to boil for at least 1 minute.
  3. Remove the water from the heating area and let it cool down. It often takes 30 minutes to cool, so boil as much in advance, especially for disasters or emergencies.

How do I kill E.coli in my water?

Using systems with filtration like a water ionizer, distiller machine, and reverse osmosis system is powerful enough to kill bacteria like Escherichia coli (E. coli), Salmonella bacteria, and Campylobacter. 

CDC also recommended that filtration systems can efficiently kill smaller germs, viruses, and protozoa that other water systems can overlook. You can manually install this in your kitchen sink or ask for assistance from the manufacturer company or local plumber. 

It’s also important to note that reverse osmosis systems may not be the best for emergencies and disasters as they need electricity to make purified water instantly. Water distillers are more emergency-friendly as some brands do not rely on electricity to work, but it removes healthy minerals and other impurities.


You may have other questions about ensuring clean water aside from does freezing kill bacteria. Here are some answers to related questions about purifying your water!

What is the best way to remove chlorine from tap water?

Purification methods that use filtration, such as a distiller and reverse osmosis system, can help remove chlorine and other contaminants naturally and most effectively. 

Water Defense also shared that most RO systems are considered the fastest and can remove chlorine up to 97.5%. You can also boil water for around 15 to 20 minutes to successfully purify chlorinated water.

How long does tap water need to sit to get rid of chlorine?

It will take 1 to 5 days to eliminate chlorine from your water. Letting your water sit to evaporate chlorine in the air is one of the slowest processes. But you can speed up the process by boiling it for 15 to 20 minutes before letting it sit.

How long should tap water be boiled to purify?

Tap water should be at a rolling boil temperature of 212F altitudes above 5000 feet (1000 meters) for 1 minute. After this, proceed to boil your water for another 3 minutes. No lingering impurities in your water can survive longer than 30 minutes in boiling water at 160F.

Wrap up: Answering does freezing water kill bacteria?

Freezing water alone cannot kill chemicals and bacteria. This also applies to overall food safety and cooking food, as freezing it will not kill harmful microorganisms. Properly heating food and storing it will prevent bacteria from thriving.

Quality filtration systems like reverse osmosis or water ionizer can help improve water quality by destroying pollutants to avoid waterborne diseases and infections like diarrhea, nausea, etc. 

Knowing how to purify your water helps improve your overall quality of life and protects your health.