Water filters can indeed remove chlorine from tap water, addressing a common concern for many households. Chlorine is intentionally added to public water supplies as a disinfectant, a practice that has significantly reduced waterborne diseases over the past century. While beneficial for public health, its presence can affect water’s taste and odor.
Understanding Chlorine in Tap Water
Chlorine is introduced into municipal water systems primarily to eliminate harmful microorganisms like bacteria, viruses, and protozoans that can cause illnesses such as cholera and typhoid fever. This process ensures water safety from source to tap, killing pathogens and providing a residual protective effect. Additionally, some systems use chloramines (chlorine and ammonia compounds) for a more stable, longer-lasting disinfection residual and fewer byproducts than free chlorine.
The Science Behind Chlorine Removal
The most common and effective method for removing chlorine from household water is through activated carbon filtration. Activated carbon is a highly porous material, treated to create a porous network with a large surface area. When chlorinated water passes through activated carbon, chlorine molecules adhere to the carbon’s surface through a process called adsorption. This physical adsorption occurs because the attractive forces between the carbon and the chlorine are stronger than the forces keeping chlorine dissolved in water.
Beyond physical adsorption, activated carbon also removes chlorine through a chemical reaction known as catalytic reduction. In this process, the carbon acts as a reducing agent, converting free chlorine into harmless chloride ions. For chloramines, the removal mechanism is primarily catalytic decomposition, where the carbon’s surface facilitates the breakdown of chloramine molecules into innocuous substances like nitrogen and chloride. This reaction for chloramines is generally slower and requires longer contact time or specific catalytic carbon formulations for effective removal compared to free chlorine.
Common Water Filter Types for Chlorine
Various types of water filters utilize activated carbon to address chlorine in tap water. Pitcher filters provide a convenient, portable option for filtering drinking water in small batches, often using granular activated carbon. Faucet-mounted filters attach directly to the tap, delivering filtered water on demand for drinking and cooking.
Under-sink filters are installed beneath the sink and typically connect to a dedicated faucet or the existing cold water line, offering a higher volume of filtered water than pitchers or faucet mounts. These systems reduce chlorine, chloramines, and other contaminants. For comprehensive treatment, whole-house filters are installed at the main water supply line, ensuring all water entering the home, including that used for bathing and laundry, is chlorine-free. Shower filters, specifically designed for showerheads, remove chlorine and other substances that can affect skin and hair, and use media effective at higher water temperatures.
Selecting Your Ideal Chlorine Filter
Choosing the right water filter involves considering several practical factors to ensure it meets specific household needs. Certification by organizations like NSF International is a strong indicator of a filter’s performance, with NSF/ANSI Standard 42 specifically addressing aesthetic issues such as chlorine reduction, taste, and odor. Examining the filter’s capacity and lifespan is also important, as this indicates how many gallons of water it can filter before requiring a cartridge replacement, influencing long-term maintenance frequency and cost.
Flow rate, measured in gallons per minute (GPM), is another consideration, especially for whole-house systems, as it affects water pressure throughout the home. An adequate flow rate ensures that multiple fixtures can be used simultaneously without a noticeable drop in pressure. Installation and ongoing maintenance requirements, such such as filter cartridge changes, should align with user preferences for ease of use. Finally, while the primary focus might be chlorine, considering a filter’s broader capabilities can address additional water quality concerns.