Most undesirable mineral in water is
Iron in water leads to discolouration and failure of metal pipings. Zinc leads to an undesirable astringent taste and greasy film while boiling Copper stains laundry like Iron Chronic consumption of water with lead causes plumbism Park's Textbook of Preventive and Social Medicine, 25th edition, Page No. 780
Iron
Copper
Zinc
Lead
Environment and health