What to Look For in a Water Filter

Water filters come in a dizzying array of options. From plastic pitchers and refrigerator filters to faucet or under-the-sink models and whole house systems, it can be hard to decide what type is best for you.


To narrow down your options, consider what you want the filter to accomplish. It is important to make sure that the filter will work in the conditions where it will be used as well.


Most filters use a form of absorption, most commonly granular activated carbon (GAC), to remove unwanted tastes and odours from the water. This is because carbon is incredibly effective at attracting and adsorbing molecules that are chemically unbalanced. The surface of carbon is jam packed with nooks and crannies that can trap a wide range of chemicals such as chlorine and dissolved organic matter. Activated carbon can be made from a number of different materials such as coconut shell, coal, wood and more. Chemicals are sometimes added to the carbon during activation to produce a surface that is more effective at adsorption of certain contaminants such as heavy metals.

The adsorption process works through electrical attraction and energy differences at a molecular level. This causes the molecule to physically fasten to the surface of the adsorbent material like a magnet sticks to a refrigerator door. This is a common natural phenomenon that can be seen in a variety of applications including the separation of sugar from crystals, air purification and the desalination of seawater.

Some water filters may also be able to eliminate pharmaceutical residue from the water, such as synthetic or natural chemicals found in prescription and over the counter medicines. This is often a concern for consumers because when consumed these chemicals can have adverse effects on health, such as disrupting the immune system or altering thyroid hormone levels.

Chemical Compatibility

A water filter’s chemical compatibility is an important consideration. Incompatible chemicals can interact to produce dangerous chemical reactions that can result in severe physical damage and even personal injury or death. Chemical-material compatibility testing is needed to ensure that production, fracturing, completion and storage fluids are compatible with the materials used in the system’s components and tanks.

Many different types of water filters are available. Choosing the correct one depends on your specific requirements and budget. Carbon filters, for example, reduce odor and taste from chemicals by confining them in their massive internal surface that’s filled with nooks and hooks. Ceramic water filters are more expensive, but they can remove pesticides and minerals from the water using ion exchange.

Another common type of water filter is a sand- or clay-based mesh filter that allows contaminated water to pass through while keeping out larger particles such as sand, dust and rust. Similarly, a ceramic water filtration system removes impurities from drinking water by allowing water to pass through its tiny pores.

Finally, an ultraviolet water filtration system kills viruses, bacteria and other pathogens by divulging the water into a beam of ultraviolet light. UV-based filters tend to be more portable than other types of water filtration systems and are also the most affordable option for households that don’t need to remove dissolved chemicals from their drinking water.


The sequestration process involves chemically isolating a material. For instance, scale-inhibiting filters use food grade polyphosphate to isolate the calcium and magnesium minerals that produce limescale and corrosion. However, it is only introduced in trace amounts and inhibits the minerals rather than eradicating them. For this reason, it is not a common method of water filtration.

Another popular type of water filtration is reverse osmosis. This involves passing the water through a semipermeable membrane under high pressure. The membrane filters out almost all the dissolved solids and impurities. This method can filter up to 1 micron, meaning that it is capable of removing cysts such as giardia and cryptosporidium.

Water filtration systems are used for many purposes, from producing better-tasting drinking water to cleaning the body and the environment. It is important to understand the different types of filters and how they work so that one can choose the right one for the purpose. This will save money and ensure that the water is safe for all purposes. It is also essential to be aware that not all filters will eliminate every contaminant, so one should examine the Consumer Confidence Report and other sources to find out which chemicals may be present in the local water supply. In addition, the filter should be compatible with any chemicals that might be filtered through it in order to avoid cross contamination.

Filtration Medium

A filtration medium is the material that separates solid particles from a fluid. It can be a thin barrier such as a filter cloth, a screen or standard laboratory filter paper. A thicker barrier can also be used such as a bed of graded granular solids like gravel, sand or coke. A precoat of filter aid may be applied to the barrier to reduce its resistance to fluid flow.

When selecting a filter medium, identification of the liquid to be filtered and its particle size should occur. Particle size is important because the larger the particles, the more likely they are to clog or block the filter. Additionally, the maximum liquid flow and pressure that a filter is designed for should be considered. It is better to oversize a filter medium than to undersize it and risk system failure due to insufficient working conditions.

Water filters are available in a wide variety of styles from plastic pitchers and refrigerator filters to faucet and under the sink models. Whole house filters that combine several types of filter mediums to treat the entire household’s drinking water are also available. The type of water filter that is best for a home depends on the contaminant removal needs. Water containing fluoride, for example, requires a special type of water filter to remove it from the water supply.