How Is Water Hardness Measured?

If you’ve noticed signs of hard water in your home, like buildup on plumbing fixtures, soap scum on shower doors or difficulty producing a lather, you may be wondering just how hard your water is.

Measuring water hardness can help you determine what kind of water softener will best meet your needs. To prepare for the next steps to soft water, learn how to assess your water hardness, understand the results and apply your findings.

Testing for Water Hardness

Hard water is typically a result of high concentrations of dissolved minerals, mainly calcium and magnesium, in your water supply. Depending on the source of your water, you may be more or less likely to have hard water problems, and well water users are particularly susceptible to this issue.

Check With Your Supplier

This isn’t an option for households that use well water, but if you have city water and you suspect you may have problems with hardness, you might want to contact your supplier as a first step.

Your local water supplier’s website and annual report are good places to begin acquiring information about general water hardness levels in your area. However, the information included in annual reports varies by location, so your supplier may not provide data on this topic. Even if relevant information is available, it will apply broadly to hardness levels in your area. The results won’t tell you how hard the water is in your household.

To find out about the specific hardness levels in your home water supply currently, you’ll have to conduct testing.

Test Your Home Water Supply

There are a variety of different home testing kits available for determining the relative concentration of hardness minerals in your home water supply. Home and lab testing options are available from water treatment professionals, too. Working with a water treatment company can help ensure that you not only get the most accurate results but understand how to interpret them and what steps to take next.

Water Hardness Measurement Scales

Understanding your test results requires familiarity with the different water hardness measurement scales that are used. Most findings are delivered as a number that reports the concentration of calcium carbonate or calcium carbonate equivalents for a given unit of water. This result may be expressed in grains per gallon (gpg), parts per million (ppm), or milligrams per liter (mg/L).

Grains per Gallon

how to measure hardness in waterAccording to the Water Quality Association, the hardness scale, measured in gpg of calcium carbonate, can be represented as follows:

  • Less than 1 gpg is considered soft
  • Between 1 and 3.5 gpg is considered slightly hard
  • Between 3.5 and 7 gpg is considered moderately hard
  • Between 7 and 10.5 gpg is considered hard
  • More than 10.5 gpg is considered very hard

Parts per Million and Milligrams per Liter

Often, water hardness test results will be delivered in ppm or mg/L, which are equivalent.

To use the same hardness scale above, you can simply convert your ppm or mg/L by dividing that number by 17.1 to find the gpg equivalent. So, for example, 130 mg/L or ppm would be 7.6 gpg, which is considered hard water.

For a quick reference, this water hardness scale used by Health Canada, breaks down results in mg/L and ppm as follows:

  • Less than 60 mg/L is considered soft
  • Between 60 and 120 mg/L is considered medium hard
  • Between 120 and 180 mg/L is considered hard
  • More than 180 mg/L is considered very hard

Using the Water Hardness Scale for Water Softener Selection

If you do notice that you have hard water, a water softener can help rid your home of issues like limescale buildup, dry hair and skin, spotty dishes and inefficiency of water-using appliances.

With a reliable water hardness test and information about your household water usage, you’ll be able to work with a professional to determine what kind of water softener will best suit your needs. Based on where your home water supply falls on the hardness scale, as well as your family’s softness preference and how much water they use, you can find a softener that suits your requirements.

Test Your Water for Hardness and Take Action

Hard water isn’t something you just have to put up with. If you notice any of the troubling signs, from clogged pipes to a filmy residue on your hair or skin after showering, make sure to measure the hardness level of your home water supply.

Once you know where you stand, you can find appropriate solutions to meet your household’s needs. Industry professionals can help you conduct testing and explore your options.