What Is Reverse Osmosis & Is It Really Healthy? 2025

Is your tap water truly safe? With growing concerns about lead, pesticides, and pharmaceutical residues, many Americans question what they're really drinking. Standard filters often fail to remove these harmful compounds, leaving families vulnerable despite their best efforts.

Reverse osmosis offers a solution that filters water at the molecular level and removes up to 99% of contaminants. But with concerns about "demineralized" water, is this filtration method the perfect answer—or does it create problems of its own?

Let's explore what reverse osmosis really is and whether it deserves a place in your home.

» Filter your tap water using a Full Cycle Method

What Is a Reverse Osmosis System and How Does It Work?

A reverse osmosis (RO) system uses pressure to push water through a semi-permeable membrane. This membrane allows only water molecules to pass while blocking harmful contaminants.



» Discover how reverse osmosis water can boost your health

What Does Reverse Osmosis Remove from Water?

• Sodium and Minerals: RO filters reject dissolved minerals like sodium and desalinating water [1].
• Fluoride: This chemical, harmful at high concentrations, gets removed by membranes in the RO system.
• Pharmaceuticals: RO systems are effective in removing pharmaceutical contaminants like fluoxetine (an antidepressant), achieving removal rates as high as 98.8% [2].
• Heavy Metals: RO filters can remove heavy metals such as lead, arsenic, and nickel.
• Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS): PFAS, a group of persistent environmental pollutants, also get removed by RO membranes [3]. But, there's some concern about the leaching of PFAS from the membranes themselves later down the road.
• Microorganisms: While RO filters have membranes that aren't specifically designed to kill bacteria or viruses, their pore size is small enough to block these microorganisms.
• Organic Compounds: Filtration devices with RO membranes can remove various organic contaminants, including pesticides and herbicides, depending on their molecular size and charge.

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What Reverse Osmosis Doesn't Remove from Water

• Certain Dissolved Gases: RO filters aren't effective at removing dissolved gases like carbon dioxide and hydrogen sulfide. These gases can pass through the membrane because they aren't ionized and have small molecular sizes.
• Some Low-Molecular-Weight Organic Compounds: Small organic molecules, such as pesticides or volatile organic compounds, may pass through the RO membrane if their molecular weight is low enough.
• Certain Pharmaceuticals: Although RO can remove many pharmaceuticals from the water, its efficiency varies. For example, it removes about 98.8% of fluoxetine, but it may miss other compounds with smaller molecular sizes.
• Oil and Grease: RO membranes are not designed to handle oil and grease in water, which can cause fouling and reduce system efficiency. Pretreatment steps, such as using adsorbents, are necessary to address this issue.
• Microbial Toxins: While RO filters can block bacteria and viruses due to their small pores, they don't neutralize microbial toxins that may already be present in water.

» Check out the differences between reverse osmosis and distilled water

Is Reverse Osmosis Water Healthy?

If you drink reverse osmosis-treated water, you avoid exposure to harmful substances like heavy metals, chlorine, and bacteria. These contaminants can irritate the digestive system, so RO water ensures clean hydration, which supports optimal digestion.

Drinking RO water over time may lead to health concerns, including mineral deficiencies. Important minerals like calcium, magnesium, and potassium, essential for bone strength, heart health, and muscle function, are stripped away during the reverse osmosis process.

It can also disrupt electrolyte balance, potentially affecting hydration, muscle performance, and nerve signaling. Symptoms might include fatigue, muscle cramps, and dehydration.

To counteract these effects, you can try the Mayu Water’s Full Cycle, which treats your water in 3 steps:

1. Remove contaminants with a countertop RO system.
2. Add the MAYU Essential Minerals Drops to revitalize the water.
3. Use the Mayu Swirl to aerate the water and improve hydration.

Purify and Remineralize Your Water

Eliminate impurities and enjoy safe, healthy hydration every day.

Step 1: Filter

Step 2: Remineralize

Step 3: Aerate

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How to Choose a Reverse Osmosis System

Selecting the right RO system is crucial for clean, healthy water.

Here are key factors to consider:

• Filter Quality: High-quality RO systems remove up to 99% of contaminants, including harmful heavy metals (lead, mercury) and bacteria (E. coli, salmonella). Look for NSF/ANSI 58 certified filters.
• Water Efficiency: Traditional RO systems waste water (up to 4 gallons per purified gallon). You should choose efficient models with permeate pumps or zero-waste systems to save money and the environment.
• Mineral Balance: RO filtration removes essential minerals like calcium and magnesium, impacting taste and nutrition. Filters with a remineralization step or MAYU Essential Minerals Drops can restore these vital nutrients.
• Installation and Size: Under-sink models require professional installation. Consider compact systems for limited space, and full house systems for severe contamination. Just remember that full house systems need higher water pressure and are more expensive.

Do This Before Buying an RO Filter:

• Test your water to identify specific contaminants.
• Calculate long-term costs (filter replacements, water usage).
• Troubleshoot common issues, like low water pressure.

» Check out our list of the best filters for smelly water

How Often Do You Need to replace RO Filters?

1. Sediment Filters: Every 6–12 months. They trap larger particles like dirt and debris, preventing clogging in subsequent filters.

2. Carbon Filters: Carbon filters remove chlorine, odors, and taste, generally need replacement every 6–12 months

3. RO Membrane: Responsible for removing dissolved impurities. Typically lasts 2–3 years but may need earlier replacement if you live in a hard water area.

4. Post-Carbon or Polishing Filters: These enhance water taste and are replaced every 12 months or as needed.

5. UV Lamps (if included): Replace annually to ensure effective microbial disinfection.

Factors Affecting Replacement Frequency

• Water Quality: Poorer source water quality (e.g., high TDS or sediment levels) may require more frequent replacements.

• Usage: Higher daily water consumption can reduce filter lifespan.

• Manufacturer Recommendations: Always follow the specific guidelines provided by your RO system's manufacturer.

Signs It's Time to Replace Filters

• A noticeable change in water taste or odor.

• Reduced water flow from the system.

• High TDS levels in filtered water (measurable with a TDS meter)

» Check out the best countertop water filters that remineralize water

Your Water, Your Health

Reverse osmosis effectively eliminates dangerous contaminants your standard filters miss, providing cleaner, safer drinking water.

The mineral loss, while real, can be addressed through remineralization filters or a nutrient-rich diet. Your ideal water solution depends on your local water quality, health needs, and environmental concerns.

Understanding reverse osmosis—both its strengths and limitations—helps you make the best choice for your family's health, now and in the future.

If you want a comprehensive water solution that addresses both purification and remineralization, consider trying the MAYU Full Cycle system. This innovative product combines reverse osmosis purification with remineralization and structured water technology, offering a complete approach to healthy, great-tasting water.

Filter and remineralize your tap water with the MAYU Full Cycle

Ensure your drinking water is pure, balanced, and rich in essential nutrients.

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