Hardness as CaCO3

GENERAL INFORMATION
Hardness does not pose a health risk to humans. In fact, calcium and magnesium in your drinking water can help ensure you get the average daily requirements for these minerals in your diet.

Hard water classifications:

  • soft 0 - 17.1 parts per million (ppm)
  • slightly hard 17.1 - 60 ppm
  • moderately hard 60 - 120 ppm
  • hard 120 - 180 ppm
  • very hard 180 or more ppm

AESTHETIC EFFECTS
Hard water can cause mineral buildup on plumbing pipes and fixtures that can lead to lower water pressure and lower efficiency of electric water heaters; can cause build-up of deposits on dishes, utensils and laundry basins; and can cause soaps and detergents to perform poorly. It can also affect the the taste of the water making drinks like coffee taste bitter.

Input units: 
mg/L
ppm
Display name: 

Hardness as CaCO3

Contaminant group: 
Action is optional 1: 

ACTION IS OPTIONAL
There is currently no health-based standard for Hardness in drinking water.  Hardness levels exceeding 120 ppm should be considered for treatment. 

Typical range in Ohio: 
150-600
Range qualifier: 
higher range values in northwestern Ohio bedrock aquifers
Major sources in drinking water: 
Erosion of earth materials
Treatment options: 

TREATMENT OPTIONS
Treat hard water by adding a water softener to laundry and the dishwasher or by installing an ion-exchange system to treat all of your household water. Ion exchange can increase the sodium content of the water, which may pose health concerns for your household.

Website resources: 

WATER RESOURCES

  • Ohio Department of Health - Private Water Systems Program - Water Quality
Fact sheets: