InspectAPedia®   -   Search InspectApedia

boiling water on stove top (C) Daniel FriedmanHow to boil water for drinking: Details of Using Boiling Water to Purify or Sterilize Drinking Water

How to boil drinking water for safe use: here we provide the details of just how long to boil water to sterilize it for drinking purposes. We give water temperatures needed and time durations needed for safe drinking water.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Guide to Boiling Water for Drinking

This article series outlines methods to purify or sanitize drinking water in an emergency following a disaster such as an earthquake, flood, or hurricane.

If drinking water is of questionable purity, boil the water for at least five minutes, and/or add bleach, and/or distill drinking water before using if a distiller and electrical power or an alternative heat source are available. See information on water treatment under the "Disaster Supplies Kit" section of some public documents.

Boiling water can kill nearly all microorganisms except, as author Matthew Stein points out in When Technology Fails, prions - which are not often present in a water supply. Remember however that boiling water will not reliably remove most chemicals nor will it remove radioactive contamination.

Even if there has been a loss of electrical power, natural or LP gas may be available at some buildings, allowing you to boil water to produce safe drinking water in an emergency. Our page top photo shows a pot of cold water that has just been placed on a natural-gas fired stovetop to begin the boiling procedure. Tip: your water will boil faster and you'll waste less fuel if you keep a top on the container during heating.

Safety Warning: do not enter a building nor attempt to use gas appliances in a building if there is a smell of gas odors or if the gas piping and appliances have been damaged by a storm, earthquake, or other event.

How Long to Boil or Heat Water for Drinking Purposes 
Water Temperature Over
Fahrenheit degrees
Water Temperature Over
Celsius Degrees
Minimum Required Water Heating Time for Purification 
160 degF 71. degC 30 minutes
185 degF 85 degC 5 minutes
212 degF 100 degC 1 minute

In most environments, the length of time that water is exposed to temperatures of 185 degF. or higher between the time it reaches 185 degF. and the time that it reaches boiling at 212 degF. is sufficient to kill most organisms and pathogens in the water.

That's why experts have not suggested that you need to boil the water for more than a minute or so. If you are boiling water on an unusually hot powerful heat source, boil it a bit longer to be safe.

Typically, experts recommend three minutes of rolling boiling water at sea level altitude to safely disinfect water for drinking.

References on boiling drinking water for safe consumption

 




ADVERTISEMENT





Reader Comments, Questions & Answers About The Article Above

Below you will find questions and answers previously posted on this page at its page bottom reader comment box.

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2021-04-13 by (mod) - reader disagrees with boiling drinking water for more than one minute

@Anon,

Thank you for catching and challenging the text of this page - indeed it needs clarification and perhaps outright need correction just as you suggest. I'll review and edit the text for clarity and make sure it's correct.

I agree that for treating bacterial contaminants, if water is boiled properly and sufficiently, it can be up to 98% effective [in treatment of common viruses (like coronavirus, hepatitis, rotavirus), bacteria (like eColi), and protozoa (like giardia or cryptosporidium)] ...(Sari 2019) (NYS DOH) but that's not exctly the whole story, and "boiling" as a term can sometimes be a bit over-simplified.

Watch out:Not everyone understands the importance of "rolling boil" and some start timing their minute when they see a few bubbles appearing in the "boiling" water container. That's a mistake. When you see those "fish eye" bubbles not all of the water has been heated to its boiling point (212°F or 100°C at sea level).

For clear water or water that has been filtered to make it clear, you should bring the water to a rolling boil and keep it rolling for at least one minute. At an altitude above one mile increase the rolling boil time to three minutes.

For example, on boiling time for water in an effort to make it safe to drink,

Watch out: we don't know the quality of the water with which we're starting. In this article series we include material on providing drinking water in emergencies. Around the world that sometimes means starting with water that's not even clear of sediment and debris. Experts have pointed out that in that circumstance it may be appropriate to boil water longer for safety.

It's worth noting that it is not just the temperature to which we raise water in an effort to kill pathogens, but also the duration of time needed at that higher temperature.

Some killing of pathogens in water begins even before the water has reached the boiling point; the "boil for a minute" guideline is generally right but there are plenty of exceptions that argue for longer boiling time or even for the need for other disinfection methods.

You can see that when we need more time to kill more-persistent pathogens, and if we are bringing our water to the boiling point quickly, the duration of heat-exposure up to the boiling point is reduced, so the total "hot time" is reduced; that's where the "boil it a bit longer if you brought it to a boil quickly" advice originated.

Of course none of the content here is invented out of thin air - we also have cited sources both above on this page and also in the references section.

Thank you for taking time to write - we can use all the editing help we can get. If you can add a couple of citations from your "all the leading health authorities" that would be useful to provide here for other readers.

Oh and on any of our pages at the bottom see additional source citations.

On 2021-04-13 by Anon

This article is full of inconsistencies. The chart says to boil water at sea level for 1 minute. Then it states that "If you are boiling water on an unusually hot powerful heat source, boil it a bit longer to be safe." Then below that it says "Typically, experts recommend three minutes of rolling boiling water at sea level altitude to safely disinfect water for drinking."

The answer given by all the leading health authorities is to boil water for 1 minute at sea level altitude. If you're above 6500ft then add another couple of minutes.

On 2017-02-08 by (mod) - how long to boil clean tap water to make it safe: 1 minute +

@Anonymous,

Tap water in most countries and cities is pretty clean of sediment and debris; in those cases, unless testing has found a specific hard-to-kill pathogen, boiling tap water for a minute (if you're at or close to sea level) will be sufficient.

Keep in mind boiling is only addressing pathogens in drinking water, like bacteria and some cysts. It may do little to remove some chemical contaminants if those are present as well.

On 2017-02-08 by Anonymous

If you're not sure about tap water how long should you boil it .


...

Continue reading at CERAMIC FILTERS for WATER DISINFECTION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Suggested citation for this web page

BOILING WATER for DRINKING at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER TREATMENT SYSTEMS

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Questions & answers on boiling drinking water for safe use: how long, what temperature, preparation of the water.

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification
when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Comment Form is loading comments...

Citations & References

In addition to any citations in the article above, a full list is available on request.



ADVERTISEMENT