How Much Mineral Content Is in Hard Water?

As water travels throughout the earth and ultimately to your faucet, it picks up minerals along the way. Water quality can be either hard or soft, depending on the type of minerals the water collects.

Mineral Content

• Hard water contains higher levels of calcium and magnesium than soft water. The higher the content of these minerals, the harder the water.

Measurements

• Water mineral content can be measured in two ways: milligrams per liter (mg/L) and grains per gallon (gpg). Water containing between 121 and 180 mg/L is considered hard. Water containing more than 180 mg/L is considered very hard. Water containing between 7 and 10.5 gpg is hard. Water with mineral content above 10.5 gpg is considered very hard.

Health Considerations

• Though hard water can cause household problems, it poses no adverse health effects. According to the National Research Council, hard water can contribute to calcium and magnesium dietary intake, depending mineral content levels.