Despite the water being treated, most water supply systems are quite contaminated with microbes as well as many different pollutants.
Therefore, it is necessary to filter and purify the water to make it safe for consumption. In this context, many people ask themselves the question, how do water filters work?
Knowledge of how filters work is necessary if we are to be able to select an appropriate water filter system for our homes.
To answer the question how do water filters work, it is also necessary to be aware of the kind of pollutants that are present in city water supplies. Chlorine is the most commonly used disinfectant in water supply systems. It is true that chlorine does disinfect water to a certain extent. However, it does not remove all bacterial and viral contaminants. For this reason, the water that comes out of our taps is not really sterile, though we usually believe it to be so.
Adding to this problem, chlorine itself is a dangerous substance. It can damage body organs and processes if it is consumed along with water over the long term. Chlorine is also absorbed into the body through pores in the skin when we take a shower or bath. Heated bath or shower water produces chlorine vapors that can aggravate asthma and cause respiratory problems.
Chemical pollution exists in water because of agricultural and industrial activities. This is an ongoing problem. In addition, natural sediments can also seep into the water supply.
So how do water filters work to guard against these pollutants? All filters are based on separating water from the substances / organisms that pollute it. However, all filters are not made equal. Some are more effective at removing particulate matter but not dissolved chemicals, while others don't do a good job of eliminating disease causing bacteria.
Carbon filters are among the more commonly used filters. They do their work by absorbing polluting substances (these substances form a chemical bond with the carbon and are hence removed from water) and filtering out larger particulate matter present in water.
Reverse osmosis is another process where the water is sent through a special membrane which does not allow pollutants through to the other side. Some water filter systems make use of distillation - water is heated to create vapor which is then condensed back into pure water. This process gets rid of chemical pollutants and other substances.
Keep in mind that every filtration system has its limitations and strengths. Therefore, it stands to reason that the best water filters are those that use more than one type of filtration. A multi-stage filtration process can eliminate a lot more pollutants than a single type of filter ever can.
Unfortunately, it is known that some filters remove not only the contaminants, but also essential minerals like calcium and magnesium. Both reverse osmosis and distillation can do this. The problem is that our bodies need these minerals to be present in trace amounts in water. Long term consumption of demineralized water can lead to serious health issues. So this is another issue to watch out for.