Carbon filters must be replaced regularly to avoid buildup of deposits. Cartridge replacement frequency depends on quantity of water used and the amount of carbon. If you are considering an activated carbon filter, look carefully at the cost of replacement filters and compare the average length of use per cartridge. Also, look at the ease of cartridge replacement. Filter systems are installed at the point of use and can be mounted under the sink, on the sink, or on the faucet.
Carbon filters are generally on cold water lines in kitchens or bathrooms to filter drinking water.
It isn't common to have a carbon filter for the complete house water system unless a specific problem, such as radon contamination, occurs. Line pressure forces water through the fibers. Particles are trapped in the filter material and removed from the water. Maintenance and replacement considerations are similar to carbon filters. Some fiber filters can be backwashed to remove trapped particles.