Hardness

Measures the concentration of calcium and magnesium in the water. Water that is hard (121-180 mg/L) to very hard (>180 mg/L) can cause scaling in pipes and appliances, reducing their efficiency, while soft water (0-60 mg/L) can taste salty. Hard water can also cause soap and shampoo to be less effective when bathing, leaving residue on skin and hair, which can result in dryness and irritation.