What causes hard water and is it safe?

Hard water is a common water quality characteristic that affects many homes. While it can be a nuisance, it’s not a health hazard.

What is hard water?

Hard water contains high concentrations of dissolved minerals, primarily:

• Calcium - A beneficial nutrient your body needs
• Magnesium - Another essential mineral for health

These minerals naturally dissolve into water as it moves through soil and rock, especially limestone and chalk formations.

Measuring hardness:

Water hardness is measured in grains per gallon (gpg) or milligrams per liter (mg/L):

• Soft: 0-3.5 gpg (0-60 mg/L)
• Moderately hard: 3.5-7 gpg (60-120 mg/L)
• Hard: 7-10.5 gpg (120-180 mg/L)
• Very hard: Over 10.5 gpg (over 180 mg/L)

Is hard water safe?

Yes, hard water is completely safe to drink. In fact:

• The EPA does not regulate hardness because it’s not a health hazard
• Calcium and magnesium are beneficial minerals your body needs
• Some studies suggest hard water may contribute to dietary mineral intake
• Hard water poses no safety concerns for drinking or cooking
• The World Health Organization has not identified health concerns from hard water

Effects you might notice:

In your home:

• White scale or mineral deposits on faucets, showerheads, and fixtures
• Reduced efficiency of water heaters (scale buildup)
• Spots on dishes and glassware
• Soap and shampoo don’t lather as well
• Bathtub ring and soap scum
• Stiff or dingy laundry
• Reduced water pressure from mineral buildup in pipes (over many years)

On your skin and hair:

• Soap is harder to rinse off completely
• Hair may feel less soft
• Some people experience dry skin
• These are cosmetic effects, not health concerns

What affects hardness levels:

Hardness can vary based on:

• Your water source (groundwater is typically harder than surface water)
• Seasonal changes in source water
• Geological formations in our water source area
• Natural variation in mineral content

What we do:

• Monitor mineral content as part of our regular water quality testing
• Focus our treatment on health-related contaminants as required by EPA

Treatment softening is not required by EPA because hardness is an aesthetic concern, not a safety issue. Many communities, including ours, do not soften water at the treatment plant.

Managing hard water in your home:

If you find hard water problematic, you have options:

Home water softeners:

• Ion exchange systems that remove calcium and magnesium
• Replace minerals with sodium or potassium
• Require regular maintenance and salt/potassium addition
• Typically installed at your main water line
• Can be costly to install and operate

Alternatives to softeners:

• Cleaning products designed for hard water
• Vinegar solutions to remove mineral deposits
• Detergents formulated for hard water
• Water conditioners (magnetic or electronic) - effectiveness varies
• Point-of-use filters for drinking water if you prefer the taste of softened water (see How can I improve the taste of my drinking water?)

Important considerations for softeners:

• Water softeners add sodium to your water (may be a concern for low-sodium diets)
• Some people prefer the taste of hard water
• Softened water may not be ideal for watering plants
• Your plumber may recommend not softening cold water to kitchen taps
• Backwash from softeners should not be discharged to septic systems in some areas

EPA secondary standard:

While not enforceable, the EPA has established a secondary standard (guideline) for hardness of 250 mg/L. This is purely for aesthetic purposes and not related to health or safety.

Hard water is a natural characteristic that many people prefer, while others choose to treat it at home. Either way, your water is safe and meets all EPA health standards.