Stains on Plumbing Fixtures
What causes discoloration on sinks, tubs, and toilets? If the stains or water are blue-green in color, then most likely, corrosion of copper is occurring within the household plumbing. Stains that are various shades of yellow, tan, brown, black, orange, or red can indicate the presence of metals other than copper. Two other metals that are typically to blame for staining are iron and manganese. While these minerals serve as essential nutrients for your body, they aren’t so kind to plumbing fixtures, appliances and even clothing. Reddish and yellow-tan discoloration is often caused by iron, while black or dark brown discoloration points to manganese. Due to their similarities and their frequent occurrence in tandem, iron and manganese are generally treated in much the same way. Discoloration usually results from the exposure of these metals to oxygen, known as oxidation. In your plumbing, water often has limited exposure to oxygen, keeping any soluble (ferrous) iron or manganese