Complete Guide to the Types of Filters for Domestic Water Treatment

Domestic water filters are the tools that help improve the quality of the water we use every day—a fact that’s now well known. Their purpose and operation are equally familiar: they remove impurities, harmful substances that can affect health and potentially corrode pipes, and unpleasant tastes. This results in cleaner, safer water for consumption, protecting health and promoting the well-being of those who use it.

However, there are several types of water filters available, each designed to meet specific needs and employ different filtration technologies. It isn’t always easy to know which one to choose, so let’s take a look at the main categories of filters and their features.

Main Types of Filters for Water Treatment

Activated Carbon Filters

Activated carbon is one of the most effective and economical technologies for treating domestic water. These filters are natural, eco-friendly, and ideal for removing organic compounds, chlorine, pesticides, herbicides, and unpleasant odors. Thanks to their dense porous structure, they trap impurities and chemicals efficiently. Activated carbon filters are commonly used for basic filtration in both pitcher filters and under-sink systems. Although their lifespan can vary, they generally need to be replaced every 12 months to maintain peak performance.

Sediment Filters (Pre-filters)

Sediment pre-filters are designed to trap larger solid particles found in water, such as sand and rust. Often installed at the entry point of the filtration system, these filters help extend the life of the main filters—like activated carbon or reverse osmosis units—by reducing maintenance needs and improving the overall efficiency and longevity of the system.

Mechanical Cartridge Filters

Similar to sediment filters, cartridge filters provide mechanical filtration to remove solid particles such as sand, rust, and sediment. They are available in various levels of filtration (measured in microns) and can be installed either as pre-filters or as standalone filtration systems. Cartridge filters can be either washable or replaceable and are particularly useful for reducing water turbidity.

Magnetic Filters

Magnetic filters work by altering the polarity of certain minerals in the water, preventing them from adhering to surfaces and forming scale. Unlike polyphosphate filters, they do not release chemicals into the water and require little to no maintenance. They are an ideal eco-friendly solution for combating limescale and are easy to install at points of use, such as under the sink.

Polyphosphate Filters

Not generally recommended for domestic filtration systems, polyphosphate filters are specifically designed to counteract limescale buildup by releasing polyphosphates into the water. These substances help prevent scale deposits, thereby protecting the surfaces of pipes and appliances. They are particularly suitable for safeguarding water heaters, boilers, and washing machines. However, regular recharging of the polyphosphates is necessary, based on water usage.

Reverse Osmosis Filters

Reverse osmosis is one of the most advanced water purification technologies available. This method employs a semi-permeable membrane that can block up to 99% of impurities, including dissolved salts, bacteria, viruses, and heavy metals like lead and mercury. It is ideal for those who desire extremely pure water. However, reverse osmosis systems require a more complex installation, consume more water, and also remove beneficial minerals. Therefore, they are generally recommended only for those using well water or natural spring water.

How to Choose the Right Domestic Water Filter

Choosing the right filter depends on several factors, including the quality of the water in your area, its intended use (whether for drinking, appliance protection, or aesthetic purposes), and your specific needs.

If your water comes from the public supply, it is generally treated but might still contain chlorine or other disinfectants, microplastics, sand particles, and heavy metals that can leach from old or poorly maintained pipes. In fact, while the purity of water is guaranteed at the treatment plant, public authorities are not responsible for what happens as the water travels through the final stretch of piping to your home—a responsibility that falls to property owners and managers.

In such cases, a combination of an activated carbon filter and a pre-filtration system can often be sufficient to improve the taste and purity of your water. This approach avoids unnecessary additional expenses while ensuring the safety and health of your family. It enables you to drink and use pure, safe water at a lower cost than bottled water, without the hassle of frequently carrying heavy water crates from the supermarket, and reduces your environmental impact by minimizing the use of plastic bottles.