The two-stage water filter system uses a 5.0-micron filter for sediment and a 0.2-micron filter for protection against contaminants. This enhanced protection removes or reduces bacteria like Legionella and E. Coli, and cysts like giardia. They offer filters specifically for rust as well. If you use your RV water to wash your rig as we do, you can swap filters to use the Deionizing Filter Kit during the wash.