Reverse Osmosis: Advantages and Disadvantages

Reverse osmosis is often presented as the most "advanced" water filtration solution, however, it is not always the most suitable choice for every household. It is a system with a high degree of efficiency in specific conditions, but it also carries its own technical requirements, a different maintenance cost and installation requirements.

In today's guide, we analyze the real advantages and disadvantages of reverse osmosis, see in which cases it justifies the investment and in which cases a simpler antimicrobial water filter covers your needs equally well, so that you can decide based on the data of your own region and consumption.

What is Reverse Osmosis and How Does It Work?;

Reverse osmosis is a water treatment process in which water is forced through a semi-permeable membrane under pressure. This membrane allows water molecules to pass through while retaining dissolved salts, pollutants, and other substances found in it. For a more technical introduction, you can also check out our detailed guide to reverse osmosis. What is reverse osmosis water?, while the international frameworks for drinking water quality are described by World Health Organization.

In domestic applications, the membrane is accompanied by multiple pre-filtration stages and a final flavor stage. In Olympus Plus reverse osmosis system, the process includes four distinct stages: a polypropylene filter for solid particle retention, a solid activated carbon filter, the reverse osmosis membrane, a final T33 carbon filter and finally a pressurized storage tank. The cooperation of these stages allows the treatment of even demanding forms of water, such as brackish or water with increased nitrates.

The Advantages of Reverse Osmosis

High Level of Filtration in Multiple Stages

The main difference between reverse osmosis and conventional filters is in its membrane. As water is forced through such small pores, substances are retained that conventional filters cannot handle to the same extent. The result is a cleaner product, especially in areas with problematic water quality.

Addresses Complex Water Problems

Reverse osmosis is suitable for hard water, water with nitrates, arsenic and brackish water. It is, therefore, a solution that makes sense when your local network presents specific and persistent issues that a classic filter cannot fully cover. In island areas or in places with brackish sources, this capability becomes critical.

Stable Availability via Reservoir

The built-in storage tank acts as a reserve of filtered water. So, even if the membrane itself produces water at a slow rate, the user enjoys an immediate flow whenever they turn on the tap. The Olympus Plus system delivers 150 to 180 liters per twenty-four hours, with the tank filling in 3 to 5 hours depending on the network pressure, comfortably covering the needs of an average household.

Wide Range of Removable Substances

The system helps remove sediment, rust particles, heavy metals, chlorine, nitrates, calcium-magnesium salts, sodium (sea salt) from brackish water, microorganisms and other harmful substances. It is a solution that simultaneously covers many categories of pollutants, without the need for separate devices for each.

The Disadvantages of Reverse Osmosis

Installation Required

In contrast to a Countertop filter Easily installed by the user himself, reverse osmosis requires a plumber for its proper connection. The installation process takes about an hour, however, it requires the appropriate conditions at the installation site and additional costs for workshop services.

Specific Hydraulic Requirements

The system operates properly at a network pressure of 3 to 7 BAR and a water temperature of 5 to 40 degrees Celsius. In homes with unstable pressure or very low values, additional adjustments, such as a pressure booster pump, may be required before the installation is complete.

Space Under the Sink

The device, including the tank and four filtration stages, takes up significantly more space than a classic undercounter filter. Therefore, it is worth considering in advance whether your sink cabinet can accommodate the unit along with the other items already there.

Multiple Filters to Replace

The complexity of the system means that there is not one single replacement part but several, with different replacement frequencies. In practice, the polypropylene filter is changed every 3 to 6 months, the activated carbon filter and the final T33 every 9 to 12 months, while the membrane every 12 to 18 months depending on use. The maintenance costs accumulate compared to a classic single-cartridge system.

It's Not Always Necessary

In households where tap water meets the basic parameters set by EU Directive 2020/2184 on water intended for human consumption and the issues are mainly taste, chlorine odor or solid particles, a Antimicrobial filter above or below the counter It covers everyday needs equally effectively, with clearly simpler installation and lower maintenance costs.

Reverse Osmosis vs. Antimicrobial Water Filter

Before you decide, it's worth taking a look at the main differences between the two types:

The table does not reveal a "winner", but helps to match the technology to the actual water profile of your area.

Cost, Maintenance and Lifespan

The total investment in a reverse osmosis system is not limited to the initial purchase price. The cost includes the plumber's fee for installation, as well as annual maintenance that includes replacing the filters at different intervals. The membrane, for example, can last 12 to 18 months depending on the quality of the incoming water.

In contrast, an Olympus Plus antimicrobial water filter with a filtration capacity of 12 months or 8,000 or 14,000 liters maintains low and predictable maintenance costs, as only one cartridge change per year is sufficient. For a household without particular network issues, the cost-benefit equation usually leans in favor of the antimicrobial filter.

When Does It Make Sense to Choose Reverse Osmosis?

Reverse osmosis is mainly justified in cases where the local network presents consistently elevated nitrates, particularly hard water, brackish areas or a strong presence of salts that conventional filters cannot regulate to a satisfactory degree. In Attica, for example, the quality of the network is constantly monitored by the EYDAP, so it is worth checking local data before making a decision. In many urban areas, tap water already meets the required parameters and the whole discussion shifts from treatment to issues of taste, odor and microbial hygiene at the point of consumption.

When an Antimicrobial Water Filter Is Enough

If the network in your area is generally good and your concern is about taste, chlorine, heavy metals or microbes inside the device, the OlympusPlus antimicrobial water filters cover most needs with greater ease. They utilize the registered Greek patent, are manufactured in Greece by the company Center Plus, and are available in above and below counter versions, as well as in versions with double or triple stages for additional protection against salts or nitrates.

For those living in rented homes or wanting to avoid plumbing interventions, the above-counter filter remains the most practical solution. For those seeking a discreet and permanent installation, the under-counter filter is a balanced choice between convenience and completeness of filtration.

Frequently asked questions

Is Reverse Osmosis Better Than a Classic Water Filter?;

The comparison is not one-sided. Reverse osmosis offers a higher degree of filtration in difficult water conditions, but a classic antimicrobial water filter is more than adequate for most household applications. The right choice depends on the actual network issues in your area. For more detailed guidance, read the water filter selection guide.

What is the Cost of Reverse Osmosis Over Time?;

In addition to the purchase price, consider the plumber’s fee for installation and annual maintenance. Pre-filters are changed every 3 to 12 months depending on their type, while the membrane usually lasts 12 to 18 months. Overall, the annual maintenance cost is higher compared to a single-cartridge antimicrobial filter.

How Often Do I Change the Filters in a Reverse Osmosis System?;

Each stage has a different replacement frequency. The first filter is changed every 3 to 6 months, the activated carbon filters every 9 to 12 months, and the membrane itself every 12 to 18 months, depending on the volume and quality of the water being treated.

Is a Plumber Needed for Installation?;

Yes, the installation of the unit is carried out by a plumber and takes approximately one hour. The aim is to properly connect to the mains supply and securely place the tank inside the sink cabinet.

In Which Cases Is Reverse Osmosis Not Needed?;

When the water in your area does not present serious issues such as elevated nitrates or brackish water, an above- or below-counter antimicrobial filter adequately covers daily needs, with a much simpler installation and lower maintenance costs.

In conclusion

Reverse osmosis is a powerful water treatment technology, with clear advantages in difficult conditions and equally numerous disadvantages in terms of installation, space and maintenance costs. Its choice should not be based on the impression of an «advanced» solution, but on the real water issues in your area. Consider local water quality data, available space and long-term maintenance, and look for the solution that truly suits your needs. View the range in the category Olympus Plus water filters and contact us for a personalized proposal.

Ioannis Giotis

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