I've never used the supplied onboard filter. I prefer to use the inline filter that can be connected to the outside water inlet. That gives me a better indication of the condition of the filter itself, requires no special tool, and doesn't require doing all sort of contortions to check/change the onboard filter. Also filters water before going into the fresh water tank, removing any spores etc., that may be in the campground water, and can grow inside the FW tank.
Ed (N4RWU) & Becky Taylor
Mistie (Walks 4-down)