Comparing 5-Stage and 6-Stage Reverse Osmosis Systems: Which is Right for You?

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Water purity is a paramount concern for many households and industries. To address this, reverse osmosis (RO) systems have become increasingly popular due to their ability to deliver high-quality water by removing contaminants. Among the available options, the 5-stage and 6-stage RO systems are commonly considered by consumers. While both systems guarantee a commendable level of water purification, understanding the distinctions between them can guide users to make an informed choice tailored to their specific needs.

5-Stage Reverse Osmosis System:

  • Sediment Filter: Removes large particles such as dirt, rust, and sand.
  • Granular Activated Carbon (GAC) Filter: Removes chlorine and other volatile organic compounds.
  • Carbon Block Filter: Further removes chlorine, as well as bad taste and odor.
  • Reverse Osmosis Membrane: Removes up to 99% of total dissolved solids (TDS), including heavy metals, fluoride, and many other contaminants.
  • Post-carbon Filter: Polishes the water to remove any remaining taste or odor before it comes out of the faucet.

6-Stage Reverse Osmosis System:

  • Sediment Filter: Same as the 5-stage system.
  • Granular Activated Carbon (GAC) Filter: Same as the 5-stage system.
  • Carbon Block Filter: Same as the 5-stage system.
  • Reverse Osmosis Membrane: Same as the 5-stage system.
  • Remineralization Filter: Adds back some of the essential minerals like calcium and magnesium that were removed during the RO process.
  • Post-carbon Filter: Polishes the water, removing any remaining taste or odor.

Key Differences: 5 stage vs 6 stage reverse osmosis

Mineralization: One of the main differences is the remineralization stage in the 6-stage system. This is often desirable because RO-filtered water is slightly acidic and lacks minerals that are naturally present in water. Adding them back can improve taste and possibly offer some health benefits.

Cost: A 6-stage RO system will generally cost more than a 5-stage system due to the additional remineralization filter.

Maintenance: A 6-stage system will require replacement of one additional filter, adding a bit to the ongoing maintenance cost and effort.

Water Taste: Because the 6-stage system adds back minerals that are removed during the RO process, many people find that the water tastes better compared to the output from a 5-stage system.

pH Balance: The 6-stage system often results in water that is more pH-balanced, whereas a 5-stage system may produce slightly acidic water.

Space: The 6-stage system will require slightly more space to accommodate the additional filter.

5 stage vs 6 stage reverse osmosis- Comparison Table

Here’s an in-depth comparison table between a 5-stage and 6-stage reverse osmosis system:

Feature5-Stage RO System 6-Stage RO System
Number of Stages5 stages6 stages
Sediment FilterRemoves large particles like dirt, rust, and sand.Same as 5-stage
Granular Activated Carbon (GAC) FilterRemoves chlorine and other volatile organic compounds.Same as 5-stage
Carbon Block FilterFurther removes chlorine, bad taste, and odor.Same as 5-stage
Reverse Osmosis MembraneRemoves up to 99% of TDS including heavy metals, fluoride, etc.Same as 5-stage
Remineralization FilterNot presentAdds back essential minerals (e.g., calcium, magnesium).
Post-carbon FilterPolishes water to remove any residual taste or odor.Same as 5-stage
Water TasteNeutral to slightly acidic taste (may vary).Enhanced mineral flavor due to remineralization.
pH Level of WaterSlightly acidicMore pH balanced due to remineralization
CostGenerally less expensiveGenerally more expensive due to added stage
MaintenanceRequires replacement of 5 filters.Requires replacement of 6 filters.
Space RequirementTakes up less spaceSlightly more space needed for the extra filter
Overall PurificationHigh level of purificationEven higher due to mineral addition

This table should provide a quick overview of the differences between the two systems. However, it’s essential to remember that the exact features and effectiveness can vary based on the brand and model of the RO system. Always check the product details and reviews when making a purchase decision.

What are the basic components of a 5-stage RO system?

Answer: A 5-stage RO system usually consists of a sediment filter, granular activated carbon (GAC) filter, carbon block filter, reverse osmosis membrane, and a post-carbon filter. These components work in tandem to purify water by removing contaminants and improving taste and odor.

What additional component does a 6-stage RO system have?

Answer: A 6-stage RO system has an additional remineralization filter that adds essential minerals like calcium and magnesium back into the water. This stage improves water taste and may balance the pH level of the water.

Does a 6-stage system produce better-tasting water?

Answer: Many people find that water from a 6-stage system tastes better due to the remineralization stage, which adds back essential minerals that are naturally found in water. However, taste is subjective, and some may not notice a significant difference.

Is the water from a 5-stage RO system safe to drink?

Answer: Yes, the water from a 5-stage RO system is generally safe to drink as it removes a wide range of contaminants. However, it’s slightly acidic and lacks minerals, which some people may find less appealing in terms of taste.

How often do I need to change the filters?

Answer: The frequency of filter changes depends on the brand and model, as well as your water usage and the quality of your source water. Typically, sediment and carbon filters need replacement every 6-12 months, and the RO membrane every 2-3 years. For a 6-stage system, the remineral


Choosing between a 5-stage and 6-stage reverse osmosis system fundamentally boils down to individual preferences and requirements. While the 5-stage system offers a high degree of purification and is often more budget-friendly, the 6-stage system takes water treatment a step further with the addition of remineralization, potentially improving water taste and pH balance.

Both systems provide a trusted method of water filtration, but the decision should be based on factors like taste preferences, budget considerations, and space availability. Regardless of the choice, prioritizing water quality is always a commendable step towards ensuring better health and well-being

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Dr. Peter Gleick

Dr. Peter Gleick is an experienced water filtration engineer and technical writer for He is an expert in water purification and filtration, focusing on helping people get clean, safe, and healthy water for domestic use. He has more than 10 years of writing experience and has numerously contributed to leading publications in this field.

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