Within the U.S., the Environmental Protection Agency (EPA) is responsible for setting national health-based standards to ensure our drinking water supplies are safe and protected from contaminants. In 1974, Congress passed the Safe Drinking Water Act (SDWA) to protect public health by regulating public water systems.¹ Since then, the EPA has set legal limits and regulations for over 90 contaminants that are found in drinking water.² The EPA then works with each state and their public water systems to ensure its water quality standards are being met.

The EPA also monitors and collects data about unregulated contaminants that may be present in our water, or contaminants of emerging concern (CECs).³ Every five years, the EPA publishes a new contaminant candidate list with contaminants that have been identified in public water systems but aren’t regulated yet.⁴ After determining the adverse health effects, the prevalence of the contaminant and if it warrants a national regulation, the EPA may create new regulations to better protect the public’s health.⁵

Before creating a new regulation, the EPA will take all of the data collected on a contaminant’s health effects and determine two different factors: the maximum contaminant level goal (MCLG) and the maximum contaminant level (MCL). The MCLG is a non-enforceable public health goal that considers public health but doesn’t account for a city water system’s ability to detect or effectively treat for the contaminant.⁶ Once the MCLG is set, the EPA determines the MCL, which is the maximum level of a contaminant that’s allowed in public water systems and an enforceable standard.⁷

Hardness is a measure of the dissolved calcium and magnesium in your water, and hard water is high in dissolved minerals, mainly calcium and magnesium.¹² It’s estimated that 85% of U.S. households have hard water, yet only 30% use water softeners to improve the quality.¹³ Hard water can reduce the effectiveness of soap and shampoo, leaving a soapy layer on your skin and hair.¹⁴ It can also make your laundry and dishes harder to clean and leave a layer of scum on your bathroom surfaces, water fixtures and drinking glasses. When hard water is heated, solid deposits of calcium carbonate can form, which can raise the costs of heating your water, lower the efficiency of your water heater and clog your pipes. Mineral build-up can also occur in household appliances, like coffee makers and tea kettles.

Hardness in water isn’t a health concern, but it can cause your hair to break more easily, leaving it brittle and frizzy, and even break down your nail beds and nails over time.¹⁵ To determine how hard your home’s water is, you need to evaluate the calcium carbonate (CaCO3) levels:

• Soft water is between 0–60 mg/l hardness (as CaCO3)
• Moderately hard water is between 61–120 mg/l (as CaCO3)
• Very hard water is between 121–180 mg/l (as CaCO3¹⁶

If the impact of hard water on your skin, hair or household plumbing and appliances is of concern, water softening solutions are available.