Does boiling tap water make it potable? If not, are there other ways (lifehacks) to make it potable without a filter? I saw a related question here on lifehacks, but it only adresses the taste, the answer did not specify if the boiled tap water would then be potable, risk-free to be drunk. I use this boiler, in case it helps:

water boiler

  • 5
    I fail to how this question needs a lifehack to solve any particular problem... It seems like it needs a straightforward, science-based, factual answer. Maybe it could be reworded such that it requests a lifehack for how to make water potable? Nov 15, 2016 at 22:55
  • Is the tap water potable before boiling?
    – Tin Wizard
    Nov 15, 2016 at 23:02
  • @Walt The water is not potable before boiling. Nov 16, 2016 at 0:26
  • @DangerZone, I was basically asking if that lifehack (boiling the water) already solves my problem or not. Anyway, I added a follow up question that probably resolves the issue you adequately brought up. Nov 16, 2016 at 0:32
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    Tap water is already potable generally. If it is not, you need to know exactly why it is not potable to know how to make it potable. (And inform the appropriate authorities if it is not a published issue) Nov 16, 2016 at 3:15

6 Answers 6


OK, I'm going to go out on a limb here...
To answer the question directly, the answer is an emphatic No.

If there is something 'wrong' with the water to start with, then simple boiling in a kettle will not 'fix' it.

It will not fix:-

  • Chemical contamination in any way, shape or form.
  • Biological contamination - though it will kill a lot of biological contamination it is not 100% certain.

You can improve your chances by many methods, but not with only a kettle.

Having said that,

  • if the water came straight from the tap in pretty much any "developed" country, then it's potable right out of the tap.
  • if it came from a well, stream or lake, then you cannot guarantee it to be potable.

Processes to 'clean' water, but require more than just a kettle:-

  • Sterilisation does not remove chemical contamination
  • Distillation can remove some, but not all contaminants.
    Anything that will boil off at a lower temperature than the water will move across with it, unless you have a fractional still [far too much to explain here, but some general info].
  • Reverse Osmosis - allowing 'pure' water to pass through a semi-permeable membrane; a very complex process not normally done as a single stage, but also employing additional chemical &/or bacterial filtration.
  • added a new link. Bear in mind a kettle takes maybe 2 mins max to reach whatever boiling point may be at your current altitude & then immediately switches off.
    – Tetsujin
    Nov 15, 2016 at 20:37
  • Thanks, I am Brazilian, I believe most regions here, including my own, do not have potable water straight from the tap. There are exceptions, though. Nov 16, 2016 at 0:39
  • I think the generally-used term is "developed" as opposed to "first-world". Nov 16, 2016 at 19:47
  • That's the one I was looking for - changed, thanks.
    – Tetsujin
    Nov 16, 2016 at 19:49
  • Stuff that boils off at a lower temperature than the water would go away if you simply boil the water though. Nov 19, 2016 at 13:19

From this link to REI
Boiling is not going to remove heavy metals or other toxic chemicals but a filter is also not effective against most heavy metals or toxic chemicals.

Your stove, fuel and a pot are an effective treatment system to combat the full spectrum of biological pathogens. Bring water to a rolling boil for 1 minute; if you’re above 6,500 feet, boil it for 3 minutes.


The only additional supply you need to pack along is extra fuel. Murky water doesn’t impair effectiveness. Serves as a readily available backup method in case your main filter breaks. Cons:

Time and effort required to bring water to a boil. Wait time for the water to cool. If it’s your primary treatment method, you need to pack an extra fuel container.


Yes and no.

Boiling water for a minimum time (I recall it as ten minutes, but I could be wrong) will destroy any biological pathogens (bacteria, viruses, parasites) in the water, but will not make the water chemically safe if it wasn't before boiling. If you suspect your water is contaminated with toxic chemicals (lead, cadmium, perchlorates, petroleum seepage, etc.) you should use a suitable filtration system to remove the toxins.

You may also want to boil the water if there's reason to suspect bioharzards, but most high quality filters will remove bacteria and parasites as well as dissolved chemicals. Read the labels to be sure.


I'm not a biochemist or anything, but as far as I know, boiling water will kill any biological contaminants. There can still be remnants or byproducts from them left in the water though, in addition to chemicals, heavy metals, etc.

You should filter first, then boil, if you can. Ideally, distill it.

As a general rule though, tap water should already be considered "potable" to begin with. If your town/city has put you under a boiling notice, then the boiling should suffice.


I've read that just boiling at atmospheric pressure is not sufficient to kill all bacteria - that's why we use pressure canners to raise the temperature of boiling enough that the canned food will not spoil. Boiling at atmospheric pressure seems likely to kill MOST of the bacteria, though, and therefore make spoiling much slower.


If it is already drinking water, then chemically nothing needs doing to it as storing water wont affect it chemically. (assuming you are using glass or food safe plastic bottles.)

Biologically, it depends on how long you want to store it for. If you want to store it for a few days, it should still be fine straight from the tap assuming that you are using a sterile bottle as any contamination will take time to grow. Any more than that I would treat the water after storage as you can not produce water bottled at home without any contamination.

If you store the water in a cool and dark location this will decrease growth of any contaminants. Additionally the dark will reduce the degradation of plastic bottles.

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