How to Protect Your Hair From Hard Water Hard-water hair care requires more than applying another mask or adding more oil. The goal is to remove accumulated minerals gently, reduce their continued buildup, and restore the softness and movement of the hair. Use a Shampoo Formulated for Mineral Buildup A standard shampoo may remove oil and styling residue without effectively addressing calcium, magnesium, iron, and other mineral deposits. Look for a properly formulated shampoo