Municipal and well water can carry many impurities that you donít want to drink. The 5231JA2002A water filter helps to rid your water of these impurities by passing the water through activated carbon, which traps the contaminants. We offer three different brands of the 5231JA2002A filter: The OEM LG replacement, the aftermarket Swift Green replacement, and the aftermarket Supco replacement, which is our cheapest option. The LG replacement has been tested and certified by the NSF against Standard 42 for the reduction of chlorine taste and odor. Even though the aftermarket filters arenít NSF certified, we still recommend either the Swift Green or Supco filter due to their affordable pricing and great filtration. No matter which brand you choose, the 5231JA2002A water filter should be changed every 6 months to ensure that your water remains clean and healthy.