Is hard water harmful? Advantages and disadvantages

When you turn on the tap to get a glass of water or wash your face, you probably don't think about what's in your water other than the water itself. Depending on where you live and whether you have a water softener system, your water may contain dissolved minerals such as calcium and magnesium. And these minerals can play a role in whether certain contaminants, such as lead, stay out of your water.

The more dissolved minerals, the “harder” your water. But is hard water really good or bad for you?

As engineering researchers who study water quality, we've seen both the positive and negative effects that soft and hard water can have on everything from plumbing systems to the human body.

What is hard water? Hard water is water that contains dissolved minerals such as calcium, magnesium, iron and manganese. Soft water contains lower concentrations of these minerals.

Hardness is measured in terms of calcium carbonate, CaCO₃, which is used as a reference point for comparing different minerals.

The amount of these minerals in a city's water supply varies depending on the region. This depends on both the source of the water and how the water is treated.

Communities that draw water from wells rather than surface water bodies such as lakes, streams, rivers and reservoirs often deal with hard water before treatment. As groundwater moves through the soil to the well, it absorbs minerals. However, in areas where types of rocks and sediments are more likely to dissolve in water, the water may be harder.

Impact on water supply and distribution systems

Water that is too hard or too soft can damage pipes and cause health problemsand aesthetics.

Because hard water has a higher concentration of minerals, minerals can build up in pipes, causing clogs in homes and public water systems. Hardness also creates more scale at higher temperatures, so water heaters are susceptible to mineral buildup. In areas with hard water, water heaters have a shorter lifespan.

But hard water can be good for you. While the minerals in hard water can clog pipes, a thin layer of mineral deposits in your water lines can protect you from consuming toxins that may leak from the pipe itself. Mineral-free water can cause pipes to corrode because without the thin protective layer of minerals, the water can begin to corrode the pipes, releasing metals from the pipes into the water. Drinking such water may mean consuming metals such as lead, copper, and iron.

While water that is too soft or too hard can affect your plumbing lines in different ways, there are other chemical processes besides hardness that play a role in corrosion and clogging of pipes. Therefore, there is no specific level of hardness that is a cause for concern. Water utilities take appropriate measures to adjust the level of hardness in water.

Effects on Skin and Hair

Using hard or soft water to wash your face can also have a noticeable effect on your skin and hair.

Hard water is more likely to make your skin dry. The minerals in hard water strip your skin of moisture and create deposits that clog pores.

Hard water can also strip your hair of moisture, leaving it dry and rough. Dry hair is more prone to frizz, tangling, and breakage. Mineral deposits can also build up on your hair and scalp, clogging hair follicles and causing dandruff and slow hair growth.

Many households have their own water softening systems. A water softening system can help with dry hair and skin and prevent scale buildup. However, many of these systems replace calcium and magnesium with sodium, a mineral that does not contribute to water hardness, to reduce overall hardness. The increased sodium content in water can be a problem for people on a low-salt diet.

General Health Benefits

Aside from the aesthetic and water heating issues, drinking hard water is actually good for you and has no serious side effects.

For example, the extra magnesium and calcium you consume from hard water can be a gentle solution to digestive problems and constipation.

In addition, studies have shown a positive correlation between drinking water hardness and bone health. Because calcium is an important mineral in bones, people in areas with drinking water containing more calcium may have higher bone density and be less prone to osteoporosis.

Researchers also found that drinking hard water is associated with reduced mortality from cardiovascular disease. Magnesium helps regulate the heart muscles, and calcium maintains the balance of sodium and potassium in the heart muscles, which is necessary for their function.

Whether you have hard or soft water, don't worry too much. Waterworks take appropriate measures to provide safe water to the communities they support.

To find out more about water hardness in your area, you can contact your local waterworks and inquire about the water treatment process. Private well owners can contact their state government for water testing guidelines in their area.