Can Reverse Osmosis Water Make You Sick? Find Out Here!

This page may contain affiliate links. If you buy a product or service through such a link we earn a commission at no extra cost to you. Learn more.

There is plenty of debate online about reverse osmosis being ‘dead water’ that is bad for your health and can make you sick.

But is there any legitimacy to these claims, or is it just fear-mongering?

Let’s see.

Key Takeaways

  • Generally speaking, there is nothing wrong with reverse osmosis water that could make you sick.
  • Reverse osmosis water is less likely to make you sick than drinking unfiltered water that may be contaminated.
  • Reverse osmosis does eliminate healthy minerals from the water, which is why we recommend remineralization.

Can Reverse Osmosis Water Make You Sick?

So, can reverse osmosis water make you sick?

Generally speaking, reverse osmosis water is unlikely to make you sick, and you are more likely to become ill from drinking non-filtered water with contaminants. When a reverse osmosis system effectively removes harmful impurities in your water supply, your water becomes significantly safer to drink and better for your overall well-being.

Some claims stating that RO water may not be beneficial for health stem from the removal of essential minerals during the filtration process, which is indeed true. Nevertheless, it is likely a safer choice to opt for water free from contaminants, even if it lacks calcium, magnesium, and other minerals.

Why Reverse Osmosis Water Could Be Bad for You

One important aspect to note is that excessive consumption of reverse osmosis water can lead to accelerated mineral elimination in the body. If you don’t obtain minerals from alternative sources, remineralization might be necessary. In fact, this is our recommendation.

In other words, before your drink the purified water that comes out of your reverse osmosis system, remineralize it with minerals.

Would it be preferable to solely eliminate the unhealthy contaminants from the water while retaining the beneficial ones? Ideally, yes, but with reverse osmosis, this isn’t feasible. However, remineralization offers a straightforward solution to restore essential nutrients to your water prior to consumption.

young woman drinking water

1. RO Water Lacks Minerals

Although reverse osmosis water does remove most minerals, it doesn’t necessarily mean the water is unhealthy. Your main source of essential minerals is food, with drinking water only contributing a small portion.

This doesn’t mean that the minerals in unfiltered water lack importance. On the contrary, they can be important when dietary intake falls short.

Several meta-studies have demonstrated a correlation between the intake of low-mineral water and negative health outcomes. However, it is important to note that these studies relied on outdated research methods that do not meet current standards.

2. RO Water Is Low in TDS

Another frequently made assertion is that RO water negatively affects the body and damages its mucous membranes because of its low level of total dissolved solids. Substantial evidence shows that low TDS water consumption over prolonged periods causes no adverse health effects.

In Vancouver, BC, municipal drinking water is naturally low in TDS, and most residents have been consuming it for years without any problems.

Has The WHO Really Warned Against RO Water?

In 2003, the WHO assembled a panel of experts to evaluate the potential health effects of consuming demineralized water. Their findings indicated that only a handful of minerals in drinking water, specifically calcium and magnesium, might be significant for overall dietary intake. It is worth noting that these minerals can be reintroduced into the RO water post-filtration.

After a quick Google search, numerous websites claim that the WHO has cautioned against consuming reverse osmosis drinking water. But no official announcement on any WHO-managed webpage validates this.

Solution: Remineralizing RO Water

The WHO has provided comments on reverse osmosis water, expressing predominantly positive views and endorsing its usage as a water purification method. However, the organization also proposes the addition of necessary minerals to reverse osmosis water before consumption. Specifically, they recommend incorporating at least 20-50 mg/l (ppm) of calcium and 10-30 mg/l (ppm) of magnesium.

After reverse osmosis filtration, there are various ways to remineralize the water. A straightforward option is to install a post-filter that reintroduces minerals like calcium, magnesium, and potassium, ensuring a balanced pH and a more flavorful taste. For a manual approach, consider supplementing with mineral drops or using sea salt rich in minerals.

Pros and Cons of Reverse Osmosis

  • Pro: Reverse osmosis removes a broad range of contaminants, more than almost all other water filtration methods.
  • Pro: Reverse osmosis offers water that is frequently purer than bottled water. Consequently, it eliminates any potential odor or unusual taste.
  • Pro: Reverse osmosis water effectively filters out microplastics.
  • Pro: Reverse osmosis water is available on demand, so if you have the right size unit for your needs, you will never run out of filtered water.
  • Pro: If you typically rely on bottled water, switching to RO filtration can result in long-term cost savings. There are also positive environmental benefits associated with reducing plastic usage.
  • Pro: Installing and maintaining point-of-use systems is typically straightforward, requiring no prior plumbing knowledge.
  • Pro: Certain systems can also be personalized, allowing you to connect them to your ice maker or coffee machine. You also have the option to include additional filtration measures like remineralization or UV water purification.
  • Con: According to some, the taste of reverse osmosis water can be somewhat bland. However, this can be easily remedied by using a remineralization filter before the water reaches your RO faucet.
  • Con: Reverse osmosis systems fail to distinguish between beneficial impurities like magnesium and harmful contaminants such as lead. This results in removing minerals that could contribute to your overall health.
  • Con: Certain RO systems are more efficient than others, yet all will produce wastewater ranging from .2 to 4 gallons for every 1 gallon purified.

If you have any questions about reverse osmosis water making you sick please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
Learn more about .


Information provided on BOS is for educational purposes only. The products and services we review may not be right for your individual circumstances.
We adhere to strict editorial guidelines. Rest assured, the opinions expressed have not been provided, reviewed, or otherwise endorsed by our partners – they are unbiased, independent, and the author’s alone. Our licensed experts fact-check all content for accuracy. It is accurate as of the date posted and to the best of our knowledge.

Leave a Comment: