Side Effects: Are There Any Dangers to Reverse Osmosis Water?
Written by: Gene Fitzgerald // Last Updated: Jul 21, 2023
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If you have been seeking information about reverse osmosis water filtration systems, chances are you have come across a bunch of websites warning you of the imminent danger of consuming this “dead” RO water. Scary, isn’t it?
But with all the fuss, why aren’t people with reverse osmosis systems filling our hospitals? Where are the warnings from the WHO about all the dangers of reverse osmosis?
There is either a cover-up, or maybe… the reports of dangerous RO water side effects are persistent myths. Let’s find out which it is.
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Key Takeaways
- Fact is, drinking reverse osmosis water that has low mineral content over a long period of time could affect your health, especially if you don’t eat a very balanced diet.
- But what could be even more dangerous is drinking water that has disease-causing pathogens or harmful chemicals and heavy metals.
- All the concerns about RO water and health can be taken care of by remineralizing the water after purification.
RO Water Side Effects – Is It Dangerous to Drink Reverse Osmosis Water?
First of all, what are the side effects of drinking reverse osmosis water? Is it really dangerous?
No, drinking reverse osmosis water is not dangerous, at least not in the short term. What is potentially dangerous is drinking water that has disease-causing pathogens or harmful chemicals and heavy metals. Here, RO water is the better choice compared to the possible alternative of drinking contaminated water.
While it is true that reverse osmosis removes healthy minerals from water as well as dangerous contaminants, if your choice is water that is high in calcium and magnesium but also high in lead, arsenic, and nitrates, versus water that is low in calcium and magnesium but doesn’t contain lead, arsenic, and nitrates, then the latter would be the logical choice. Plus, you can add the good minerals back into the water before you drink it, which is a win.
So what could lead to health complications is to consume low-mineral water over an extended period of time and not compensate the mineral shortage in any way. To be on the safe side, the WHO recommends reintroducing calcium and magnesium ions back into low-mineral water before consumption.
Another side effect of RO water could be very mild heartburn, as RO water is slightly acidic, but remineralizing the water would take care of this too.
It’s Safe to Drink RO Water.
Reverse osmosis filters most impurities from your water supply, making it safe for human consumption. Waterborne illness was a major cause of early mortality in the days before water treatment and still is in a lot of countries. Since water treatment methods have been introduced, water has become much safer to drink.
Good or Bad – Debunking the Myths Surrounding RO Water
Can RO Water Make You Sick?
Sure, RO water can make you sick if your RO filtration system isn’t working properly and has bacteria in it. But aside from that, if the system functions properly and is properly maintained, it cannot make you sick.
Consider RO water as a great, pure canvas. It has been washed clean of any impurities, and now it is ready for you to add minerals back in with one of the many possible remineralization processes, bringing the water “back to life”, minus the things that are going to make you sick.
Further Reading:
Does RO Water Leach Minerals from Your Body?
This one is actually backed by studies: Low-mineral water increases the elimination of sodium, calcium, potassium, chloride, magnesium, and possibly other ions from the body.
So again, do consider remineralizing your reverse osmosis water. You could add mineral-rich sea salt or enrich it using a remineralization stage.
Is RO Water Too Acidic?
Reverse osmosis water is considered acidic, but it is not considered too acidic unless you have issues with reflux. To put things into perspective, reverse osmosis water may have a pH of around 5-6.5 (neutral is 7). Lemon Juice has a pH of 2, orange juice is 3, and black coffee is 5. Soft drinks and sports drinks are often 2.5-3. So, on a daily basis, you are probably consuming beverages that are far more acidic than RO water.
Besides, RO water is acidic because it has been stripped of its minerals, meaning its alkalinity. The first thing RO water is exposed to is air, where it dissolves carbon dioxide. This then creates carbonic acid, which, you guessed it, is acidic.
The good news is that RO water is ready to absorb new minerals, such as calcium and magnesium, which are easily added back in with a remineralization step. As such, the pH of RO water can fluctuate again pretty quickly and is easy to balance out.
What Is Reverse Osmosis Water Treatment?
How Does It Work?
Reverse osmosis water treatment systems work by running your home water through multi0ple filter stages before the water is sent through the faucet. These stages of filtration remove most contaminants in the water, leaving you with almost 100% pure H2O.
Reverse osmosis itself is one of the filtration steps in this process. It involves the water being pushed through a semipermeable membrane with microscopic pores, which only the tiny water molecules can pass through. Larger (potentially dangerous) contaminants are left on the other side.
Depending on your personal requirements, the systems usually come in countertop models, under-the-sink models, or whole-house reverse osmosis systems for homes with very heavily contaminated feed water.
You can also choose what type of pre and post-treatment you like. Most common are sediment and carbon filters.
What Does It Remove?
The list of individual contaminants removed by reverse osmosis is a mighty long one, so let’s stick with the contaminant groups instead. Reverse osmosis systems remove:
- Heavy metals such as lead, cadmium, and mercury
- VOCs (volatile organic compounds)
- Microbes such as bacteria, cysts, and protozoa
- Water disinfectants such as chlorine and chloramine
- Disinfection byproducts
- Pesticides and herbicides
- Minerals and salts (sodium, calcium, magnesium, potassium, fluoride)
- Sediment and silt
- Nitrates/Nitrite
- Overall Total Dissolved Solids (TDS)
- Transition metals (iron, chromium, nickel)
- PFAS
- Microplastics
Pros and Cons
What are the pros and cons associated with reverse osmosis water purification?
- Pro: Broad contaminant removal: Reverse osmosis can remove up to 99.9% of contaminants found in water supplies.
- Pro: Reverse osmosis water is free of tastes and smells: Contaminant removal means the removal of any weird tastes and smells you may have in your tap/well water.
- Pro: Purified water available on demand: Unlike some other methods of filtration, reverse osmosis systems will have water ready for use whenever you need it, provided you have installed a system with enough water production and storage capacity for your household needs.
- Pro: Save money and the environment: RO filtration may have a bit of a startup cost, but if you are a bottled water drinker, you will save money in the long run by not having to purchase them while also reducing your consumption of single-use plastics.
- Pro: Easy to install and maintain: Most RO systems (not including whole house systems) are easy to set up and maintain yourself, even if you don’t consider yourself too “handy”.
- Con: RO water tends to taste a bit flat: Because reverse osmosis membranes remove all minerals, the water can taste a bit flat. The contaminants in water are what give it that bit of taste.
- Con: Essential minerals are removed: As discussed, RO removes beneficial minerals from the water as well as bad ones. This can be rectified with remineralization.
- Con: Wastewater: There is no getting around it; RO systems produce wastewater. Some more so than others. Be sure to ask about the predicted wastewater when purchasing, and if you find you are losing a lot, you can install a booster pump which can reduce the amount of wastewater by up to 90%.
- Con: Ongoing system maintenance: While reverse osmosis system maintenance is simple, it isn’t something you can avoid doing altogether. It is vital to periodically maintain your unit so you don’t end up drinking unsafe water.
- Con: RO water purification is a slow process: This is only a con if you use more water than you anticipate with a tank-based system. If you do, then it can take some time to refill.
- Con: Kitchen space: Under the sink, reverse osmosis units do need quite a bit of space, at least 2×2 feet. Countertop units need counter space. If you have a small kitchen, fitting a system could take a little fiddling.
- Con: You will likely need a separate faucet: Most RO systems require a dedicated faucet; you don’t just hook it up to the primary faucet you have. This can mean an extra hole drilled in your sink for installation.
- Con: Direct drain connection: You need to hook your wastewater line up to the drain pipe under your sink, which requires the installation of a drain saddle.
Remineralizing Reverse Osmosis Water
If the lack of beneficial minerals in reverse osmosis water still worries you, luckily, there are multiple solutions for remineralization.
- The easiest one is to install a remineralization post-filtration step that will add essential minerals back into your water after purifying it. This will also make the water less acidic.
- There are also products available to add minerals into your water after you have drawn it from the tap, such as remineralization drops, or if you want a quick and cheap at-home solution, a high mineral sea salt will do the trick!
If you have any questions about the side effects of RO water please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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