Activated Carbon

Activated carbon water filters reduce chlorine, chloroform, agricultural chemicals, organic matter, sediment, and magnesium.

The key to understanding how activated carbon water filters work is adsorption. As opposed to absorption, where one material absorbs or takes in another, adsorption is when one material sticks to another as it passes through. This is the basis of activated carbon, or activated charcoal.

Activated carbon is created when organic materials with a high carbon content, such as wood, coal, or coconut shells, are heated until they do not burn but become charcoal-like. The charcoal is then processed to create a porous material that can bind to certain toxins and impurities, thereby separating them from the water flowing through the system.

This is the most common type of filter and is often used in conjunction with other filtration methods to maximize toxin removal. For example, the Aquasana Whole House Filtration System is an activated carbon filtration system that combines a saltwater conditioner, copper zinc, and ore with ultraviolet light for maximum filtration.

Ion Exchange

Ion exchange water filters are beneficial for removing minerals and radioactive materials from hard water, as well as reducing lead.

As the name implies, an ion exchange filter consists of a substance that exchanges one ion for another as water flows through it. For example, ion exchange replaces calcium or magnesium ions, which are responsible for water hardness, with sodium ions. This softens the water. If your home water leaves stains on washed dishes, you probably have hard water. Hard water tends to build up in pipes, which can shorten the life of certain kitchen appliances.

While ion exchange can help remove hard water and some radioactive materials, the filter is not as effective at removing organic matter, particles, or bacteria as other filtration options. Therefore, it should be noted that ion exchange is usually associated with water softeners rather than filters, although water softeners may serve as a stage in a whole-house filter.

Reverse Osmosis (RO)

Reverse osmosis water filters are able to effectively remove a large number of toxins, including fluoride, hexavalent chromium, arsenic, nitrates/nitrites, copper, radium, salts, and more.

Speaking of bang for your buck – there’s a reason why reverse osmosis filters are so popular. Reverse osmosis filters are top-notch filters for removing a wide range of contaminants from water, which can include dangerous bacteria associated with waterborne diseases.

RO filters work by using pressure to push water through a reverse osmosis membrane. Contaminants are retained on one side of the membrane, while fresh water is pushed to the other side. It is one of the few filters that can remove water-soluble contaminants such as fluoride and chromium +6 from water. If your home has a water softener, an RO system will also remove salt from your drinking water.

While reverse osmosis systems are becoming a popular choice, their filtration process uses too much water, sometimes up to four times the normal amount of water used. The filtration process is also slow, causing a drop in water pressure. This is why whole-house reverse osmosis systems are not usually available. Additionally, this level of filtration is not necessary for everyday activities such as flushing the toilet, showering, and washing dishes. Learn more about the pros and cons of reverse osmosis systems here.

Mechanical

Mechanical water filters are good for removing physical particles such as sediment, dirt, and waste.

Mechanical filters are most often used as a pre-filtration method. They act as a barrier, and as water passes through the mechanical filter, waste gets caught between nylon strands, synthetic foam, or mats. In a fish tank, for example, the filter will capture plant material, leftover fish food, and waste, but not the beneficial bacteria that are good for the fish.

You may notice that mechanical filters have a micron rating, which indicates how effective they are at removing particles of a certain size. Common ratings include:

5 micron: removes most particles visible to the naked eye.

1 micron: removes particles too fine to be seen with a microscope.

0.5 micron: removes cysts such as Giardia and Cryptosporidium.

UV

UV water lights are a home water treatment system that is beneficial for removing bacteria and viruses.

UV filters are an environmentally friendly option that uses different frequencies of ultraviolet light to disinfect water.

UV filters use ultraviolet light, which kills essentially all bacteria and viruses after being absorbed by their DNA, thus purifying drinking water. It is important to note that UV filters only remove bacteria and viruses from the water, so this filter must be combined with other types of filters to remove common contaminants such as chlorine, lead, and pesticides to give you clean drinking water.