Can Reverse Osmosis Water Cause Diarrhea?

Can Reverse Osmosis Water Cause Diarrhea?

If you’re wondering whether Reverse Osmosis (RO) water can still end up giving you diarrhea, you’re at the right place. Waterborne diseases are one of the main risks that compel people to go for a sound water filtration system like Reverse Osmosis. We will explore whether RO water can cause stomach-related issues, like diarrhea, and its root cause.

Reverse osmosis water does not cause diarrhea because it filters out the pathogens responsible for most stomach issues, such as cryptosporidium. However, the absence of alkaline minerals and the slightly acidic pH level of RO water can cause other stomach problems like aches and cramps.

More than 3.4 million people lose their lives due to waterborne diseases, globally. This is quite an alarming number. Contaminated water can cause serious health hazards. Reverse Osmosis filters remove 98%-99% of contaminants, including the ones responsible for causing diarrhea. This makes RO water free from disease and safe to drink.

Read my comprehensive article about reverse osmosis.

Can Reverse Osmosis Systems Remove Pathogens from Tap Water?

Reverse osmosis filtration systems have gained popularity over the last few years for providing safe-to-drink water. An RO system is designed to pass water from a source through a membrane with microscopic pores in it. These membrane pores are so tiny that they only allow molecules smaller than that water to pass through them.

The RO system separates the purified water from the contaminant concentrated water. The pure water is then pushed through to a holding tank or a special tap installed in your house (mainly the kitchen). Most pathogens are bigger than water molecules and are expelled from the purified water during this process.

Advanced versions of reverse osmosis systems can also come with a UV filter. This ensures that the water is treated with UV rays before sending it to the RO membrane. UV rays can also kill the majority of diarrhea-causing pathogens in water.

Since most disease-causing pathogens like cryptosporidium are expelled from RO treated water, it is highly safe to drink and cannot cause diarrhea.

Common pathogens removed by RO system

We’ve already mentioned that the primary pathogen responsible for diarrhea and other major stomach issues, cryptosporidium, is already removed by an RO system. An RO system can also remove the following microbes and pathogens from water:

  1. Giardia
  2. Salmonella
  3. Shigella
  4. Campylobacter
  5. E.coli
  6. Hepatitis A
  7. Norovirus
  8. Rotavirus
  9. Enteric

Read my article Does Reverse Osmosis Remove Bacteria from Drinking Water to learn more.

Boiling water versus reverse osmosis

People have been boiling water since ancient times to remove pathogens. However, it is vital to remember that boiling can only kill these pathogens. So, when you drink this boiled water, you also consume the dead pathogens.

Reverse osmosis systems altogether remove these pathogens through the membrane. This ensures that the water you drink is super clean and has no traces of pathogens in it. In addition to removing pathogens, other Total Dissolved Solids (TDS) that can harm the digestive tract are also removed as compared to when you just boil the water instead of filtering it.

Does RO Water Have Any Side Effects?

Consuming RO water has no significant side effects, as clean water is good for your health. However, some concerns surround RO water consumption. Let’s look at these in detail and also some possible solutions that can alleviate these concerns:

1.   RO systems remove essential minerals from water

Salts such as sodium, calcium, and magnesium are essential minerals in the water. These minerals contribute to your heart, kidney, and bone health. Calcium and magnesium ensure healthy bone development.

Natural tap water contains these trace minerals. RO systems remove both calcium and magnesium during the filtration process. So, you essentially get demineralized water. There is no significant harm in consuming RO filtered water, but because mineral absorption is easier when you drink it, it is recommended that your water source have these minerals.

If you continue drinking low-mineral water, you can experience headaches and lightheadedness.

The best solution is to add a mineralization filter to your RO system or use mineral drops to remineralize your RO water. Read my article on remineralizing RO treated water.

2. Reverse osmosis systems make water’s pH level acidic

The RO membrane can filter out most contaminants, but dissolved gasses such as carbon dioxide can pass through it. This carbon dioxide reacts with the free hydrogen ions in water to form bicarbonate ions. This process makes the pH level of water acidic.

Usually, your body can adjust the pH level of water if it is mildly acidic. However, if the amount of carbon dioxide in the water is high, the water will be highly acidic, and it can have effects such as heartburn and hinder weight loss for those trying to lose weight.

You can fix this by adding lemon or baking soda to your water to make it alkaline or to balance the pH levels. You can also use pH drops in your water for the same purpose.

Read my article Why Is My Reverse Osmosis Water pH High?

Frequently Asked Questions

1.   Is waste water from RO systems safe to drink?

The wastewater produced from RO filtration has a very high concentration of contaminants and Total Dissolved Solids (TDS) that are incredibly harmful to your health. You should not consume this waste water as it can get you seriously ill.

2.   Can drinking reverse osmosis water dehydrate you?

Reverse Osmosis water has fewer electrolytes than other water sources, so it cannot hydrate you as much as mineralized water can. You can add mineral drops to your RO water to ensure you get the requisite hydration.

3.   What minerals should you add to your RO water?

The best mineral to add to RO water is Himalayan salt because it is rich in all the essential trace minerals that are removed by the RO membrane during the filtration process. This will remineralize your water and give it a good taste too.

Final Thoughts

RO systems are installed to deliver pure and safe-to-drink water that contains no pathogens so it cannot cause diarrhea. However, it can still have some mild side effects that are easily alleviated through the solutions we have mentioned above.

Related article: Is Reverse Osmosis Water Good for You: 3 Dangers to Know

Boch Richard

Richard Boch is a chemical engineer responsible for designing water filtration systems for industrial and residential customers. He has more than 20 years of experience with ion exchange, activated carbon, and reverse osmosis. Richard's expertise has made him a go-to source for municipalities and businesses looking to improve their water quality. When he's not working, Richard enjoys spending time with his wife and two young children.

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