by Gabe Ergler
What Does A Hardness Test Really Tell Us?
February 12, 2019
PolyHalt Defined

What Does a Hardness Test really tell us?

A discussion to answer this question can not be had without reference to the WQA (Water Quality Association) as the WQA is the defacto water treatment industry association and education leader.  We will look at how the WQA defines hard water on it’s web site.

Please note: for the remainder of this article everything in blue italic text below comes directly from the WQA web site.

“Hard water is a common quality of water which contains dissolved compounds of calcium and magnesium and, sometimes, other divalent and trivalent metallic elements. The term hardness was originally applied to waters that were hard to wash in, referring to the soap wasting properties of hard water. Hardness prevents soap from lathering by causing the development of an insoluble curdy precipitate in the water; hardness typically causes the buildup of hardness scale (such as seen in cooking pans). Dissolved calcium and magnesium salts are primarily responsible for most scaling in pipes and water heaters and cause numerous problems in laundry, kitchen, and bath. Hardness is usually expressed in grains per gallon (or ppm) as calcium carbonate equivalent.”

The part of the definition to focus on and keep in mind is how the term hardness was originally applied. This is what maters to consumers of water and it describes how the water behaves, more specifically how water containing untreated minerals (dissolved calcium and magnesium) behaves.

The WQA definition of hard water goes on as follows:

The degree of hardness standard as established by the American Society of Agricultural Engineers (S-339) and the Water Quality Association (WQA) is as follows:

What does this tell us? It tells us how different concentrations of untreated hardness minerals will make the water behave. For instance, less than 1 grain untreated mineral concentration will not have too much effect on how the water behaves. And 1 to 3.5 grain will have more effect on how the water behaves, it will behave “slightly hard”. If the water contains more than 10.5 grain untreated mineral concentration will display the most evident hard water behavior of “very Hard”. The water treatment industry erroneously uses this hardness standard to show how hard the water will behave. The only thing is really tells us is the concentration of hardness minerals.

What doesn’t this tell us? It does not tell us whether the water will behave soft or hard. The most important consideration to the quality of water is how the water behaves not the concentration of hardness minerals.

All that is needed to improve the meaning of this standard is to add a simple statement to clarify this standard refers to untreated concentrations of minerals.

Why doesn’t the water treatment industry clarify it’s definition of the degree of hardness standard? The answer to this very good question is one that ruffles more than a few feathers in industry. To much surprise during my research I found the industry has grappled with improvements to it’s definition of hardness and treatments for hardness for decades. The WQA has even had several committees over the years to work on this problem yet has not been able to provide an answer or at least an answer that is accepted by the salt-based softening sector of the water treatment industry.

The salt-based softening sector of the water treatment industry is happy with the current definitions and standards. The current degree of hardness standard does clearly provide proof as to whether a salt-based softener is working and no one can argue against clear proof something is working.

There is another side to the current definition and industry teachings that is not so good for consumers and the industry as a whole. Current definitions and standards neatly protect softening processes that remove hardness (salt-based softeners) while at the same time provide a barrier to market entry by other treatment methods such as polyphosphate softening which alters the behavior of the minerals so they don’t exhibit behaviors of hard water and don’t require removal from the water. The uneducated consumer’s choice of treatments is substantially limited by outdated and inaccurate definitions and standards.

Summarized, the best response to my research as to why the inability of the industry to adapt to advances in water treatment processes and techniques that go beyond mineral removal goes like this; We can measure effectiveness of hard water treatments that remove the minerals from the water to prove they are working by testing for the presence or absence of hardness minerals . If we measure no hardness after treatment we can prove we’ve successfully softened the water. We do not have such a test for treatments that alter the behavior of the minerals without removal of the minerals. Current hardness tests measure the same amount of hardness before and after treatment. This is not to say there aren’t other treatments that soften the water only that we can’t measure and prove successful treatment.

To this I say only two things need to happen:

  1. Modify and improve the definition of the degree of hardness standard to show it refers to untreated hardness.
  2. Focus on the original definition of hard water, the way it behaves, not on the concentration of hardness minerals. If the water acts hard it is hard, if it acts soft it is soft.

More really Good Information:

Ever wonder what hard water really is? Check our this Cascadian Clear blog post: Hard Water Defined

You likely noticed this blog does not discuss soft water, for that you will need to see our Cascadian Clear blog post Soft Water Defined.

Ever have someone test your soft water only to have them tell your your water is hard when you know it’s soft? Check out this Cascadian Clear blog post  Why Does Soft Water Test Hard?

If you wonder what a hardness test actually tell you please see our Cascadian Clear blog post: What Does a Hardness Test really tell us?

If you’d like to know more about chemical treatment of hard water see Cascadian Clear blog post: What is PolyHalt® and How Does It Work?

Do you have a salt-based softener but still have problems with spots on your glassware, shower doors and windows? Check out this Cascadian Clear blog post: Silica – The other white spot


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