How Long To Boil Water To Sterilize (And Why)?

How Long To Boil Water To Sterilize (And Why)?

Exact Answer: 20 Minutes

Water comes in use for multiple purposes like cleaning, cooking, and more. It is hence needed that the water is clean. But the case is even more sensitive when the water is being used for consumption or cooking purposes. 

Although the water looks clean, there can be many bacteria and pathogens in water that can cause problems when consumed. Since water is a basic necessity for living beings, it can be sterilized to ensure it is safe to drink or cook. 

How Long To Boil Water To Sterilize

How Long To Boil Water To Sterilize?

Sterilization is the best way to keep the water in the perfect way to consume. Sterilization kills all the bacteria and other things like viruses or diseases in the water. Water can still be contaminated even though it looks clean. Water tends to contain viruses and bacteria that can be the reason for several illnesses like Cholera, Typhoid fever, Dysentry, E.Coli and more.

There are various methods to get rid of all the bacteria and viruses in the water. The methods include disinfecting, getting it treated with chemicals. It can also include something as simple as boiling the water to sterilize it. However, since it takes time for the water to reach the boiling time, it is important to wait until it boils to sterilize it properly.

It will take about 20 minutes to sterlize the water after it boils while heating. The boiling point of the water is 100 degrees celcius, and when the heat reaches that degree, the water gets boiled. It is important to keep the water boiling for 20 minutes at 100 degrees Celcius to sterilize the water for any purpose. 

The time for boiling the water may increase on decrease because of several factors like the temperature and even altitudes. Generally, if the temperature is kept to a low setting, it will take away more than 20 minutes to properly sterilize the drinking water.

TemperatureThe time for which the water is to be sterlized
175 Degrees FahrenheitMore than 30 minutes
212 Degrees Fahrenheit20 minutes
250 Degrees Fahrenheit15 to 20 minutes

Why Boil The Water For So Long To Sterilize?

Sterilizing drinking water can become necessary for a lot of reasons. It can be due to a faulty pipeline or the cleaning system is not working. Sterilization becomes a viable option to avoid getting waterborne diseases. Sterilizing the water by boiling it takes time, and there are a few reasons for that. The reasons are as follows:

  • The primary reason behind the sterilization taking so much is the temperature. Usually, when the temperature is high, the water will boil faster, and the sterilization process will happen faster too. On the other hand, if the temperature is on the lower side, it will take more time for the water to boil. Low temperature causes sterilization to happen after a long time. The ideal temperature to boil the water is 212 degrees Fahrenheit or 100 degrees Celcius. It will ensure that sterilization will take a maximum time of 20 minutes.
  • The altitude or the pressure in the air is another factor that takes time when it comes to sterilizing the water. Higher altitudes have lower air pressure, and lower air pressure causes the water the boil faster. Hence, the sterilization process will be faster at high altitude points. Likewise, the sterilization process will take more time when it is done at a low altitude point or place where the air pressure is high. At 10,000 feet higher than the sea level, the water boils at 194 degrees Fahrenheit.
  • Some bacteria or pathogens can be stubborn, and it would take continuous boiling or constant high heat to eliminate them from the water. Hence it becomes imminent to keep the water on high heat for some time to sterilize it.


Purifying the water is necessary in cases when a person is planning a trip in the wilderness. The water out there is not proper for human consumption, and hence just boiling it is not enough. Therefore, it becomes imminent to sterilize the water.

It can prove to be fatal as well if the water from natural sources is consumed without sterilization.


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Hi! I'm Nidhi.

Here at the EHL, it's all about delicious, easy recipes for casual entertaining. So come and join me at the beach, relax and enjoy the food.

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