Brown staining is iron, the most common water treatment problem in wells.
Ferrous Iron (dissolved) the most common type of iron is not visible, When Oxygen is mixed with Ferrous Iron it satins sinks, toilets and laundry, especially if bleach is added. To reduce the levels of Ferrous Iron, aeration, softening or a combination of both can be done.
Ferric Iron (suspended) is oxidized and forms floating particles. Treatments used are cartridge filters or a backwashing filter.