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How to Test Water Hardness?

Hard water, often known as water hardness, is a common water property containing dissolved calcium and magnesium compounds. You might be curious about how hard your water is if you’ve witnessed signs of hard water in your homes, such as soap residue on shower doors, build-up on plumbing fixtures, or trouble lathering.

You might be curious as to what causes water to be hard or soft, whether or not hard water is dangerous, why the concentration of particular minerals causes water to be hard, and how to evaluate water hardness. Therefore, we’ll cover everything you need to know to test the hardness of water in this blog post.

What Exactly is Hard Water?

Hard water contains dissolved magnesium and calcium. It is measured by the is the quantity of these contaminants present in the water. These contaminants combine with fatty acids in soap to create an insoluble foam that reduces the effectiveness of the soap and can cause soap scum buildup. Here you can read more about hard water compared to soft water.

How Is Water Hardness Measured?

High levels of dissolved minerals, primarily calcium and magnesium, in your water supply are usually the cause of hard water. The likelihood of you experiencing hard water difficulties depends on its source. For instance, home well water users are especially vulnerable to this problem, and thus, testing water hardness is compulsory. Here are three types of water hardness tests.

Quick At-Home Soap Test

The simplest way to test your water for hardness without going too far is to use a clean, empty bottle, tap water sample, and pure liquid dish soap. Fill one-third of the bottle, add a few drops of pure liquid soap, and shake the bottle ferociously for a couple of seconds.

Hard water will have fluffy bubbles noticeably absent and the water will appear hazy or milky. Soft water will have clear water in the bottom of the bottle and will have a lot of bubbles in it. Use a basic soap devoid of colors, fragrances, and detergents for the best results.

Check With the City

Most towns provide a yearly report with information on the findings of their hard water tests. You’ll know what to expect regarding your home’s water hardness based on your city’s results. Local statistics will provide a solid starting point for understanding water hardness measured in different units, but you must still know how to test it precisely in your home.

professional water testing

Advanced testing

A test strip, similar to a test for swimming pool or spa water, is one of the most straightforward procedures. Look for a clean bottle made of glass or plastic with a tight-fitting cap. Straight from the faucet, fill the bottle until it is 1/3 full. After submerging the water test strips in the water, examine the color against the water hardness test kit color chart. The results will show you the hardness level of the water.

You can easily find various water test kits from different brands. They constitute several test strips and a color chart with guidelines to measure the carbonate hardness levels of the water.

What Is the Hardness Water Scale?

According to the Water Quality Association, you can measure the hardness of the water in milligrams per liter (mg/L), grains per gallon (gpg), or parts per million (ppm).

While there is no ideal water hardness level, knowing the various water hardness testing scales is essential to understand your test results. Results are in a numerical value indicating the amount of calcium carbonate or calcium carbonate equivalents present in a given water unit. Here is a short reference for the water hardness scale, show results in both mg/L and gpg:

Grains Per GallonMG/L OR PPMWater HardnessEffect
Below 1Between 0- 17.1SoftNone
1 to 3.5Between 17.1 – 60Slightly HardNone
3.5 to 7Between 60 and 120Moderately hardDry skin and spotty dishes
7 to 10.5Between 120 and 180HardClogged pipes and clogged water heater
More than 10.5More than 180Very hardClogged pipes and clogged water heater
Short reference for the water hardness scale.

Does A TDS Meter Measure Water Hardness?

Are you trying to determine the hardness of your water using your TDS meter? You can’t, that’s for sure! If that wasn’t the response you were searching for, we apologize. Why it won’t function is as follows:

A TDS meter is a tiny, portable instrument used to measure the amount of total dissolved solids (TDS) in a solution, often water. It is a measurement of everything dissolved in your water. A TDS meter measures water’s electrical conductivity and uses this information to calculate the TDS value.

TDS contains much more than hardness, making it challenging to determine hardness with TDS measurements alone. Yes, a significant portion of the TDS will contain hardness mineral content when the water is hard, but not all of it. As a result, your TDS measurement will always be much greater than the hardness number.

What Is the Best Way to Measure Water Hardness?

One of the best ways to measure water hardness is to refer to professionals. Although there is home testing that people often find the easiest, referring to professionals will ensure accurate results. You should send your water to a reputable water testing lab for the most thorough water hardness analysis.

These companies offer a range of testing, from basic checks to see if your water measures up to EPA drinking requirements, to health checks. These labs use more sophisticated advanced testing kits to determine the number of toxins in your water. The results assist you in deciding whether you need further filtration for your drinking water.

Addressing Water Hardness Issues

There are a few different ways to address your water hardness issues once you know the amount of hardness minerals.

  1. Ion Exchange Water Softeners: These systems exchange calcium and magnesium ions with sodium or potassium ions, effectively reducing water hardness. They are generally installed where water enters the home.
  2. Salt-Free Water Conditioners: This type of system doesn’t reduce hardness but rather crystallizes the minerals so they don’t form scale on plumbing and fixtures.
  3. Reverse Osmosis (RO): Often used under the sink for drinking water, RO systems can reduce many types of contaminants, including minerals that cause water hardness.
  4. Magnetic and Electronic Descalers: These devices claim to alter the electromagnetic properties of the minerals in the water to reduce scaling, but their effectiveness can be inconsistent.
  5. Chelating Agents: Chemicals like EDTA can be used to bind with the calcium and magnesium ions in water, preventing them from precipitating out as scale.

The Bottom Line

Many homes have hard water, which can harm many appliances, including sinks, dishwashers, showerheads washer and dryers, you name it. However, by testing your water using the three simple procedures outlined above, homeowners can halt the flow of hard water and get rid of it from your home before it causes any damage. At DROP, we suggest using a water softener to easily get rid of hard water problems.

Take the step and check your water hardness and contact us if you see any alarming symptoms, such as clogged pipes, fragile hair, or a filmy residue left on your skin. Get in touch with us today to get started.


  • https://www.aquatell.ca/blogs/aquatell/how-to-test-water-hardness-with-a-tds-meter
  • https://www.labrotovap.com/does-a-tds-meter-measure-hardness/
  • https://aurigaresearch.com/water-testing/how-to-measure-water-hardness/
  • https://www.thespruce.com/how-to-test-for-hard-water-1824904
  • https://www.usgs.gov/special-topics/water-science-school/science/hardness-water
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