Re: Micron Rating The smaller the micron rating, the smaller the size particle the water filter cartridge will remove. For comparison purposes, the human hair has a diameter of approximately 70 microns, and particles smaller than 40 microns are not visible to the human eye. In other words, the more sediment you want to remove from your water, the smaller the micron rating should be for your filter. Thank you, WaterFilters.NET |