I've conducted a research on how can I purify the water to make it drinkable and the results are many, but most of them says that drinking a freeze water can cause cancer to us.

I am using a freezer safe container and I put it in a freezer, let that for one day then when it is freezing I will let it thaw for maybe 6 hours, then I will put it in a water container so I can drink it in the future. Is this safe to drink? Does it kill the germs?

One of the answer in a forum is this

Cold and freezing will not kill microbes and parasites

Please enlighten me. :) I am doing it for almost a month and so far nothing bad happens to me.


3 Answers 3


The answer, briefly, is no -- freezing will not make your water safe to drink.

Freezing does damage living cells, mostly because water expands when freezing, and ice crystals can break the cell walls. Thus, some bacteria will be killed by freezing. And many larger organisms (e.g., parasites, pests) will often be killed by freezing. Long-term freezing can increase the number of bacteria killed further.

However, freezing does NOT sterilize food or liquids. It may decrease the number of bacteria present, and it will generally prevent them from multiplying. But it is not an acceptable way of purifying water acquired from an unsafe source, because many harmful bacteria will generally still survive. Also, many microorganisms have spore forms which can survive freezing much more easily and reactivate when thawed.

If your goal is to kill off most microorganisms, boiling may be an easy alternative (and may even require less energy use than freezing). However, be aware that boiling will generally not affect the levels of any dissolved chemicals that could also render the water unsafe.

  • I'm using refrigerator because there are still many spaces left in the freezer area, this is much more practical for me. Thanks for enlightening me. By the way, do you recommend to drink from the tap water (city water) that has been frozen and thawed? Is it enough to make it drinkable? Commented Dec 1, 2014 at 3:38
  • 3
    Freezing is NOT an effective treatment for anything other than perhaps some parasites. If your "city water" has been properly treated (e.g., with chlorine) to kill microbes before it comes to your house, then what you do afterward doesn't matter. It will already be "drinkable." If your water still contains things like bad bacteria, freezing will NOT make it safe. If you are putting water in your freezer just to fill it up, that's fine, but you will not improve the quality of the water by doing so. Again, freezing also requires a LOT of energy, so it's hard to justify it for little benefit.
    – Athanasius
    Commented Dec 1, 2014 at 14:25

Freezing does not generally kill bacteria, or even yeasts.

There are entire industries which rely on that fact.


I lived in Brasil for ten years and putting water from the tap into 2 liter bottles and keeping them in the freezer was common practice. We always had 3 or 4 at all times and I've never heard of anyone including myself getting sick. If you just drink water straight from the tap in south America expect to be making many unwanted trips to the bathroom

  • 2
    “We did X and nothing happened” is never a good basis for food safety, which is based on biology, chemistry and statistics.
    – Stephie
    Commented Oct 3, 2022 at 13:58

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