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Reverse Osmosis vs Distilled Water: Which One is Better?

by Jennifer Bellini

Marketing expert, Business guru

> 2 min read


Both well water and city water need to be filtered to maximize their safety, especially if you live in a home with old lead pipes. However, not all filtration systems are created equal, and your needs will vary depending on your living situation. Some filtration systems give stellar results but at a high cost.

Reverse osmosis is a popular option for kitchen water systems, but it is expensive and has a limited daily capacity. Distilled water is even purer, but it takes more time and energy than reverse osmosis. Although reverse osmosis is more practical for most people, distilled water may be necessary in some cases.

HERE ARE OTHER QUESTIONS THAT YOU MIGHT HAVE ABOUT WATER:

  • Water Filters: Do I Need This?

What is Reverse Osmosis?

Reverse osmosis uses an ultra-thin membrane with micropores to filter contaminants out of water. It can remove lead, calcium, iron, sodium, and many other helpful elements in small quantities but harmful in large amounts. It also filters microorganisms and most chemicals that can make you and your family sick, such as protozoa, like Cryptosporidium Bacteria and Giardia; E. coli, Shigella, and Salmonella bacteria; and viruses, like Norovirus, Rotavirus, and Hepatitis B.

Reverse osmosis systems usually use a separate sediment pre-filter to get sand and large minerals out and then use a chlorine filter to remove chlorine. Since reverse osmosis alone cannot completely remove chlorine effectively, a system without this filter may have a lingering chlorine taste afterward.

As a result of its removal of minerals, reverse osmosis leaves the water slightly more acidic than before. This can be remedied with an alkaline water ionizer or left alone if the pH difference is very slight.

However, reverse osmosis is regarded as an excellent option for families wanting to get purified water daily. It creates purer water than sediment or carbon filtration alone and does not take up much space. When it comes to reverse osmosis vs. distilled water, reverse osmosis will usually win based on its balance of convenience and quality.

How Does Water Distillation Work?

Distillation starts by boiling water, which causes it to turn into steam. When water becomes steam, it leaves behind most contaminants, including minerals and most chemicals. The steam can be drawn away from the contaminants left behind and condense around a condensation coil, which lowers the steam temperature until it turns back into water.

When done with a clean and well-maintained system, distillation removes the vast majority of contaminants. However, some rare contaminants with a lower boiling point than water may also boil, allowing them to travel with the water when condensed and dispensed. These situations are rare, and distillation is still the go-to option for scientists and others searching for the purest water possible for experiments and specialized needs.

The Downsides of Reverse Osmosis and Distillation

The issue of reverse osmosis vs. distilled water is complicated due to the differences in equipment and methodology. Reverse osmosis cannot filter out as many impurities as distillation, especially pesticides that can dissolve thoroughly in water.

Distillation is more time-consuming than reverse osmosis, requires a high amount of energy, and needs more space. This makes it difficult to get clean water on-demand in a residential setting. It works well in a pinch if you are staying somewhere with an older water system or an unreliable well filtration system, but setting up a distillation system for temporary use is a huge hassle.

If you have a distiller in your home, you can distill and store water ahead of time in reusable bottles. However, this process is more labor-intensive than simply turning on your kitchen sink. Some distillers have a convenient spigot for easy dispensing, but these distillers usually require manual refilling.

Getting a System Installed

Getting your local well or municipal water tested at least once a year is the best way to ensure that you get the right system installed. Some areas may have unusual underground contaminants that necessitate distillation before drinking, but this is rare and usually a sign of severe environmental contamination.

For long-term daily use, reverse osmosis is a much better option. You can get a reverse osmosis system installed under your kitchen sink and hook it up to a dedicated faucet if desired. This system takes up a small amount of space compared to a distiller, so it’s ideal for a range of kitchen and home sizes.

Standalone water distillers may be a good choice for staying in cabins or other remote locations where the water quality is suspect. However, installing a reverse osmosis system may still be a better option as long as you can do basic maintenance, like filter replacement, at least once a year.

Both standalone water distillers and reverse osmosis systems are easy to buy online and set up on your own. As long as you have some basic tools and know how to shut off your water supply, you can safely install under-counter or countertop systems without any hassle.

Keep in mind that due to the low flow rates each system has, neither distillation nor reverse osmosis is a practical option for house-wide filtration. In rare cases, reverse osmosis may be necessary for making very poor-quality water clean enough for bathing and laundry, but this is not the case in most regions. However, this becomes very expensive very fast, and other filters like carbon block filters may be a more practical compromise.

Emergency Situations

In case of a boil water advisory from local authorities, your reverse osmosis system will continue to filter effectively for up to 24 hours. Once 24 hours is up, or the boil order is lifted, you will need to replace the filter and sanitize the system.

Having a distiller on hand may be an attractive option for survival enthusiasts, especially if you have a generator on hand that’s powerful enough to run it. As long as you know how to maintain the distiller, it may serve you well in an emergency. However, its benefits do not outweigh those of reverse osmosis systems in most circumstances.


Keeping Up-to-Date

Both reverse osmosis and distilled water require you to pay attention to maintenance and frequently clean filters and other parts based on the manufacturer’s directions. However, distilled water’s quality isn’t a practical option for everyday use. 

Installing a reverse osmosis system gives you a balance of purity and practicality that allows you to get clean water directly from your faucet without wasting water bottles or having to wait to boil water.

Jennifer Bellini

About the Author

Jennifer Bellini is a business guru who’s spent most of her life working in her home state of Wisconsin where she still lives with her family. Her experience lends itself best to sussing out the unique problems a business may face with their water quality. She is also our lead market analyst and is the driving force behind site growth.