To remove rust from hair, use a hair color remover, then apply hair dye to get new color. Choose matching hair dye before removing color to get the best match.
Washing hair in iron-rich water can turn hair a rusty shade of red. The rust particles in the water absorbs under the hair's cuticle, working the same way permanent hair color works, so rust will not simply wash away. Every time hair is washed normally, the rust gets a bit harder to remove from hair follicles. That is why to get rid of rust in hair, it is necessary to strip out all the color from the affected hair.
Each manufacturer provides specific details on how to apply hair color remover, but all require clean hair without hair care products in it to function correctly. The new color can then be applied immediately after the rust and color has been stripped out of the hair.
Using water from the same source will cause the rust buildup to return. To keep the rust from coming back and discoloring the hair again, it is necessary to wash the hair with water from another source, or water that has had the iron filtered out.