Drinking Water Filters: Comparison of Activated Carbon and Osmosis
Activated carbon filters vs. osmosis filters: Which pollutants are reliably removed?
When it comes to clean drinking water, two technologies for drinking water filters are often at the center of discussion: activated carbon filters and reverse osmosis systems. Each has its specific advantages and is better suited for certain pollutants. Here is a quick overview of what these systems can achieve and what limitations they have.
Activated carbon filters
Activated carbon filters work primarily through adsorption and the fineness of the pores. Depending on pore size, they can retain substances from a certain size onward. There is activated carbon granulate, a loose material in a cartridge, and activated carbon blocks with 10, 5, 1 and also 0.5 μm pore size. The smaller the pore size, the better. Adsorption means the filters “bind” pollutants to their surface, similar to a magnet. These drinking water filters are particularly good at removing organic compounds from the water.
Activated carbon filters from the water:
• Chlorine and chlorinated hydrocarbons, which clean the water but can impair taste and odor
• Pesticides, herbicides and other chemicals from agricultural use
• Medication residues
• VOCs (volatile organic compounds, e.g. benzene), which can enter air and water
Activated carbon can also remove some heavy metals such as lead and mercury, but its efficiency depends heavily on the type of filter and the duration of use.
What activated carbon does not remove:
• Salts and minerals
• Nitrate, nitrite, phosphate
• Hardness-forming substances (calcium, magnesium)
• Microorganisms, bacteria and fungi (only to a limited extent)
The Evodrop filter represents an exception among activated carbon filters; see the box below for more.
Reverse osmosis filters
Reverse osmosis systems (reverse osmosis, RO) work with an extremely fine sieving effect that removes most dissolved substances from the water. Osmosis systems can be distinguished into:
• Systems with storage tank: rather older systems that are no longer recommended
• Direct-flow systems: The filtered water is produced on demand at 1–2 liters per minute.
• Pump-free systems without pump (no noise pollution): They require a line pressure between 2.7 and 5.5 bar. The higher the operating pressure, the more liters per minute are produced.
With osmosis systems, a separate faucet is necessary – either a 1-way faucet or a 3-way faucet. Optimal are faucets with the quality criterion “metal-free”.
Pollutants that RO reliably filters out:
• Salts and minerals: Reduces total hardness and removes ionic compounds such as sodium, calcium and magnesium
• Phosphate, nitrate and nitrite, which often enter the water through fertilizers
• Heavy metals: effective filtration of lead, arsenic, copper and other heavy metals
• Bacteria, fungi and other microorganisms
• Medication residues, pesticides and chemical contaminants
• Microplastics
What reverse osmosis does not (completely) remove:
• Volatile organic compounds (VOCs) (sometimes removed by additional activated carbon post-filters)
Conclusion of the comparison:
Activated carbon filters for everyday tap water with chemical residues and taste correction: These drinking water filters are very well suited for use against organic pollutants and chlorine. They are suitable for improving the taste and odor of the water and for filtering tap water that has been chemically treated.
Reverse osmosis filters for heavily contaminated water, especially with heavy metals, fluoride, nitrite, nitrate or microorganisms: They remove almost all dissolved substances, including heavy metals, salts and microorganisms. They are ideally suited for households with heavily contaminated water and/or in regions with high heavy metal or nitrate levels in tap water.
Recommendation: A combination of both systems (e.g. activated carbon + reverse osmosis) offers the most comprehensive protection.
• Activated carbon filter as a pre-filter: Removes chlorine and organic pollutants, which extends the service life of the reverse osmosis membrane.
• Reverse osmosis filter: Removes remaining dissolved substances, heavy metals, bacteria and microplastics.
• Remineralization (optional): Adds a few minerals back to the pure water after reverse osmosis to create better conditions for water energization (structure formation – hexagonal water structures).
Evodrop filter: Innovative process for drinking water of the best quality
Thanks to its patented ultra-nanomembrane technology, the Evodrop filter is able to remove microplastics, nanoplastics, bacteria and other substances from drinking water.
• Filtration efficiency: Typical microplastic particles have a size of less than 5 millimeters, often even under 1 micrometer – the Evodrop filter can filter out particles down to a size of 0.002 micrometers.
• Successfully tested: The Evodrop filter was tested by independent laboratories on over 614 substances. The results confirm the filter's ability to eliminate a variety of pollutants, including microplastics.
• Protection against pollutants: In addition to microplastics, the Evodrop filter also removes other pollutants such as heavy metals, pesticides, medication residues and many more from the water.
Compared to other activated carbon filters, the Evodrop activated carbon membrane is unique in terms of the quality and quantity of substances filtered out, including bacteria.
Important: Nitrate, nitrite and fluoride can only be safely filtered out by osmosis systems!
Our tips
• AQUNA Osmose Light: electricity-free osmosis drinking water filter system with pre-filtration, remineralization and UMH water activation, without tank, pump or electrical parts
• UMH Hexagon with Evodrop activated carbon membrane: easy-to-install plug-and-play system without a separate faucet