Hardness (Calcium & Magnesium)

Health Effects

Not a health hazard - calcium and magnesium are essential minerals. Hard water is primarily an aesthetic and household maintenance concern: scale buildup in pipes and appliances, spots on dishes, reduced soap efficiency, dry skin and hair.

Source: EPA National Primary Drinking Water Regulations

Where It Comes From

Dissolved calcium and magnesium from natural geological deposits (limestone, dolomite, gypsum). Water hardness is a natural characteristic of groundwater that varies by region.

Where It's Commonly Found

Very common - the U.S. Geological Survey estimates that 85% of U.S. homes have hard water. Highest in the Midwest, Great Plains, Southwest, and anywhere groundwater passes through limestone or dolomite.

Not regulated by EPA - no MCL exists. Generally classified as: soft (<60 mg/L), moderately hard (60–120), hard (120–180), very hard (>180 mg/L as CaCO3). Affects ~85% of U.S. households to some degree.

How to Remove It