Water Hardness is the measure of the dissolved mineral content in water. It measures the number of minerals left after being boiled away, which is why it’s not always obvious to notice it in our day-to-day experiences. The most common scale for normal water hardness is between 1–15 but can go up as high as 20 (very hard) or down to zero, which is soft. Hard water has a number of effects on your dishes and laundry detergent, and not all good. Below are a few examples of how water hardness can be measured.
1. Specific Gravity Method
The Specific Gravity test takes precisely 20 minutes and uses a scale of 1–200. However, this scale is unreliable for measuring water hardness in a state with low or no precipitation. The scale is calibrated to determine how “heavy” the water is relative to the number of dissolved minerals in it. As you increase the quantity of minerals, the weight of that mineral also rises. Even if your water has a specific gravity of 1, it doesn’t mean it’s HARD and will damage your washing machine!
2. The Brine Method
Water hardness can also be tested with the Brine Method. The method is based on the fact that the higher the amount of dissolved minerals in the water, the harder it is to remove them by boiling. By weighing out a known quantity of salt in grams (grams = 1/1000th of an ounce/28.3 grams), then adding as many drops as you can to a test tube with water, and then boiling them together for 20 minutes, you create a very accurate scale for measuring hardness.
3. How Well it Dissolves Potassium Chlorate White Powder
Potassium chlorate is a white, flaky powder with a molecular weight of 152. It is used in many industrial processes as an oxidant and to remove chlorine. This white substance is a strong oxidant that, when added to tap water, will cause it to turn green and stained. The effect of this can last for months. More importantly, for our purpose here, this substance will not even dissolve in soft water. This means you can use the hardness scale to test hardness without ever testing your actual water! A perfect solution.
4. The Relationship between Calcium Carbonate and Magnesium Chloride
Magnesium and Calcium are often the main minerals in water in large quantities. Their solubility is not affected by temperature, which is why this hard water scale goes to 20 (Extremely hard). Although when interacting with Sodium Chloride in a solution, it reverses this effect, which is why Soft Water (water with softener added) will evaporate faster than normal tap. Calcium Carbonate and Magnesium Chloride are both used in fireproofing and as a cement hardness additive.
These are a few examples of how water hardness can be measured. Usually, a professional water test is needed to give accurate results. However, you can use these tests on your own to get a decent feel for the hardness of your water. If tap water is hard, it is recommended to invest in a whole-home water softening system. This will protect your household appliances from the potentially damaging effects of hard water.