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Boiled Water vs. Filtered Water


Even if you’ve never experienced one yourself, you’ve likely heard of a boil water advisory. It’s important to heed boil water advisories or mandatory boil orders whenever they are put in place.

But what circumstances trigger a boil water advisory? Is boiling water always the best way to address drinking water safety?

These are important questions, especially when they impact your entire drinking water supply. Understanding the answers requires taking a closer look at what boiling water does at a microscopic level, how boiled water differs from filtered water and why boiling is sometimes necessary.

Is Boiled Water Safe To Drink?

List of contaminants boiling water can addressYou might have seen survival TV shows and movies where the main characters boil water in their remote locations, often as a rudimentary method of disinfection. But the fact that local boil-water advisories exist indicates the merit of this water-treatment approach in exceptional circumstances. What do you need to know about boiling water? Let’s take a look:

Can You Drink Boiled Water?

According to the U.S. Centers for Disease Control and Prevention (CDC), boiling water is one of the best ways to kill viruses, bacteria, parasites and other disease-causing germs* —just remember to let boiled water cool before drinking it.

What Does Boiling Water Do?

When you bring water to a rolling boil, you’re using heat to damage living organisms’ structural components and disrupt critical life processes. Keep in mind that boiling is not the same as sterilization. The former addresses contaminants that may be harmful to humans, while the latter will kill all present organisms.  Note, too, that you should not boil your water if you suspect it is contaminated with fuel, toxic chemicals or radioactive materials–the CDC recommends contacting your local health department for guidance in that event, as boiling will not make water contaminated with fuel or toxic chemicals safe to drink.

Boiling water properly, at the correct temperature and for the correct duration of time, can address health risks caused by microorganisms, including rotaviruses and some strains of E. coli.

How Do You Boil Water Properly?

Because different things break down at different temperatures, it’s important to boil your water correctly:

  • Heat: 212°F (100°C)
  • Time: One minute, or three minutes at elevations above 6,500 feet/1,981 meters

Once boiled, water can be kept in the refrigerator for three days, or at room temperature for 24 hours. Beyond this timeframe, you should repeat the boiling disinfection process with fresh water.

Remember to follow any guidelines included in a boil water advisory.

There are some things you can’t expect from boiling. For example, boiling water doesn’t remove chlorine — which, while generally harmless, can create unpleasant tastes and odors in your tap water.

Unfortunately, boiling water can also lead to a somewhat flat taste. To address this, you can let your boiled water sit for a few hours. You can also add a pinch of salt for each quart/liter of water.

Is Boiled Water the Same as Filtered Water?

Depending on the situation, boiling water can be an effective way to ensure the safety of your drinking water in an emergency, but the process at work with boiling is not the same as filtration.

Boiling uses heat to reduce the risk of harm from disease-causing organisms. Filtration, meanwhile, uses different methods — such as reverse osmosis or a series of physical sediment traps — to address water problems. 

The two approaches don’t necessarily catch the same things. For example, a whole home water filtration system may address your chlorine taste and odor concerns, while boiling will not. Similarly, boiling could help catch certain bacteria your filtration system isn’t designed to handle.

That being said, it’s important to understand that boiling water isn’t always necessary and that a filtration system is generally more than capable of handling everyday concerns. You need to boil water only in rare cases, like when a natural disaster causes extensive damage to public water infrastructure. For day-to-day water-quality concerns, filtration is generally an efficient and effective solution.

When Boiled Water is a Must

Whole home and under sink filtration systems are great for everyday use, but there are some cases when even the best filtration solution may not address concerns brought about by disruptions to the local water supply or local water-treatment facilities. That’s when a municipality will step in to issue a water advisory. If there is a water advisory in your area, you should follow the directive even if you have a filtration system installed.

Water advisories generally come in one of three types: do not drink, do not use and boil water. 

  • Do not drink: Tap water should not be consumed but can be used for bathing, cleaning and other purposes.
  • Do not use: Tap water should not be used for any purpose.
  • Boil water: Tap water should be boiled before any use.

Boil-water advisories are far more common than “do not drink” or “do not use” orders. In Canada, boil water advisories account for about 98% of drinking-water advisories each year.  In 2021, 90% of these advisories were issued due to equipment or process-related concerns, while 8% were due to microbiological parameters and 2% were related to E. coli. 

Boil water advisories are usually precautionary. That means they’re often issued before a public health threat is confirmed. However, the length of the advisory may vary depending on the severity of the issue and how long it takes to resolve it.

Why Are Boil Water Advisories Issued?

Utilities or local health agencies will issue water advisories to help protect you from current or potential water issues. They want you to be informed about what the problem is, what they’re doing to fix it and what you should do in the meantime.

If You’re Under Advisory, What Should You Consider?

No matter what kind of water advisory is in place, you’ll need to think carefully about your tap water and how it’s used in your home. While drinking water is perhaps the most obvious and important consideration, you also need to consider water used for:

  • Cleaning dishes and laundry
  • Bathing or showering
  • Washing your hands
  • Brushing your teeth
  • Providing water for pets
  • Making ice
  • Preparing food or baby formula

Should You Boil Filtered Water?

Remember, filtration doesn’t address the same issues as boiling water. This means that if a boil advisory is issued, you should boil tap water even if it’s filtered.

What Should You Do After a Boil Water Advisory?

When the water advisory is lifted, don’t return to using your tap water right away. Instead, run all cold-water lines inside and outside the house for at least five minutes and until they become clear. Run hot-water lines for at least 15 minutes for a typical household 40-gallon tank. This will flush out your plumbing and help ensure you’re getting fresh water. You should also flush water-using appliances like toilets and dishwashers.

If you have water filtration systems with individual filters, you should replace these to avoid potential contamination. Check your owner’s manual or reach out to your local water expert for help.

It’s also helpful to have a water test after a boil water advisory. Although these advisories are lifted only when your local public health organization has deemed the water supply safe for regular use, having your own test results for your residence can provide additional peace of mind.

The Benefits of Filtered Water

For day-to-day water quality concerns, adding a filtration system to your home comes with a lot of benefits — and a lot of options, too.

Two of the main types of water filtration systems are whole house and under sink. As their names suggest, these systems work in different locations and with different approaches, but both help you take control of your water quality.

Whole home water filtration systems are designed to address problem water issues throughout your home. Chlorine, sulfur, iron and sediment are just a few issues that  a whole house system can address. Some filters can even neutralize acidic water to help protect your home’s plumbing from corrosion, which can lead to different types of contamination.

Under sink filtration systems often work via reverse osmosis and focus on your drinking water quality. They can address a wide range of potential issues with your tap water, including the presence of nitrates, mercury, lead and some virus and bacteria types. They can also help address newer chemicals of concern, including PFAS and PFOA, sometimes known as “forever chemicals.”

You’ll need to choose the right system depending on your water source, home plumbing conditions and more. A professional water test and consultation can help determine which issues you’re facing and which water solution is best for you.

Regardless of which system you choose, you can expect to see a variety of benefits from water filtration. Here are just a few examples:


Boiling water is effective in addressing possible contamination by disease-causing germs, but you can’t track exactly what’s happening in the process. Water filtration systems, on the other hand, often come with smart tracking technology and smartphone apps to give you complete visibility into your home water treatment. You can get information about how your system is working and what it’s addressing, which means you can feel confident in your chosen solution.


Water filtration systems don’t require a lot of work on your part. However, when you do need to take control — for example, to track your water usage to find ways to improve your water use efficiency — your system can help. You’ll have access to the settings and guidance you need to tailor the ideal water experience.


Water filtration systems are always working, which means they typically require no extra time or effort day to day on your part. Boiling water, although sometimes necessary in an emergency, requires significant time and attention — and, unless you have a lot of pots and burners to spare, you’ll probably have to repeat the process multiple times to get enough water for cooking, cleaning and bathing. 


A good water filtration system is built to work hard, and it can notify you when maintenance is necessary so you’ll never have to be without effectively filtered water.

Environmental Friendliness

Are you tired of relying on single-use water bottles, which are bad for your budget and even worse for the environment? Water filtration systems help improve your water quality so you don’t have to turn to wasteful bottles anymore. In fact, Culligan® filtration solutions save 15 billion bottles globally from landfills every year. Smart features even allow you to track how many bottles you’re saving.

Learn More About Your Water

Although the possibility of bacterial contamination can be unsettling, a boil water advisory lets you know exactly what to do and how to do it.. However, boiling and water filtration aren’t interchangeable, which means it’s important to know which solution is appropriate for which situations.

Learning more about your water and how to ensure its quality begins with a water test and consultation. You’ll learn the causes of water problems such as odors and discoloration — and, most important, you’ll find out how to fix them.

Are you ready to take charge of your tap water? Schedule your free water test and consultation today to get started.

*Contaminants may not be present in your water. 

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