Customer Questions and Answers for Center Spray Arm And Tube Assembly by Bosch

Hello Kirk, This is normally caused by minerals or other contaminants in the water supply. There is nothing in the dishwasher that can cause this. With well water, the well walls can collapse periodically, causing muddy water and with city water, every time the city breaks into the water system to do repairs, add a line, or other maintenance type work, they can introduce contaminates into the water supply. This can also be caused by food containing tomato sauce such as chili or spaghetti sauce. You can use a cleaner WX10X10022, W10549845, W10549845 to flush the unit and sanitize it.