How to Test Water Hardness at Home: 7 Different Tests

When was the last time you tested your water hardness? Do you even know how to test your water hardness?

Testing your water hardness will help you understand why your tap water tastes funny and gives you insight into how to fix it. In addition, testing your water hardness will save you money because you won’t have to buy bottled water anymore.

I’m going to teach you everything you need to know about testing your water hardness. It’s super simple and takes just minutes to complete.

How to Test Water Hardness at Home

How do I know if I have hard water?

If you live in a large urban area, you may not notice any problems with your water until it begins to cause issues with your plumbing. The first signs of hard water include limescale buildup on faucets and shower heads, hair loss, skin irritation, and soap scum build-up.

The easiest way to determine whether you have hard water is to buy a water hardness tester at your local hardware store. Simply add a few drops of water from the sink into the sample cup and wait ten minutes. If the number reads above 50 mg/L, then you have hard water.

Methods To Test Water Hardness at Home

Test #1: The Soap Method

Soap is one of those things you never think about unless it doesn’t work properly. If you’ve ever had hard water, you know how it affects your laundry. You use more detergent and you end up with fewer suds. But what happens when you’re washing dishes? Do you notice any difference? In my experience, I don’t.

The reason why is that most dishwashing liquids are formulated to dissolve in either cold or hot water. Cold water dissolves soap faster than warm water, so you’ll end up with a thin layer of soap on your plates. Warm water dissolves soap slower, so you’ll end with a thicker layer of soap.

If you want to see what type of soap you’re using, try doing a little experiment. Take some dish soap and add a few drops of food coloring to it. Then pour the mixture into a bowl filled with tap water. Stir it around and let it sit for 10 minutes. Now, look at the color of the liquid. Is it clear or cloudy? If it’s clear, then you’re probably using regular dish soap. If it’s cloudy, then you’re using dish soap designed for hard water.

Now take a small amount of dish soap and mix it with a cup of water. Add a couple of drops of food coloring. Let it sit for 10 minutes and observe the color again. Does it remain clear or does it turn cloudy? If it turns cloudy, then you’re probably dealing with hard water.

To find out whether or not your tap has hard water, just follow the instructions above. If it’s clear, you’re good to go. If it’s cloudy…well, there’s nothing you can do except hope that your pipes aren’t too old.

Test #2: Hard Water Kit

Hard water testing kits are the best and easiest way to determine whether your water has high levels of minerals. Most kits contain some sort of strip that measures the amount of calcium, magnesium, and other minerals present in the water.

Test #3: The pH Test

The pH test measures the acidity or alkalinity of your water. This is measured on a scale of 1-14. A pH value of 7 is neutral. Anything below 7 is acidic and anything above 7 is basic.

A pH meter is used to measure the pH of your water. It looks like a flashlight with a probe attached to it. You simply dip the probe into the water and wait for the results.

If you live in an area where the water is naturally acidic (pH less than 6), you should be careful about drinking it. Acidic water can cause stomach problems such as ulcers.

If you live in an area with high levels of minerals, you may need to adjust the pH of your water by adding baking soda or vinegar. Baking soda raises the pH while vinegar lowers it.

You can buy a kit online from Just search “water hardness testing kits.”

Test #4: The Iron Test

Iron is one mineral found in water. When iron is present, it makes the water yellowish brown. In order to determine how much iron is in your water, you must use a spectrophotometer.

It works by shining light through the water and measuring the intensity of the reflected light. The higher the intensity, the more iron is present.

Hard Water Test#5: The Chlorine Test

Chlorine is another common element found in water. It’s usually added to make sure that people don’t get sick when they drink it.

In order to test for chlorine, you’ll need to use a litmus paper strip. Simply place the strip in the water and watch it change color.

When the water contains no chlorine, the strip remains blue. As soon as the water begins to pick up chlorine, the strip turns red.

Test #6: The Carbonate Test

Carbonates are compounds made up of carbon and oxygen. They are often found in water.

In order to test for carbonates, you’ll need to add a drop of potassium bicarbonate solution to some water. Then, you’ll need to observe the reaction between the two chemicals.

If the water becomes cloudy, you know that it contains carbonates. If the water clears up, then you’re safe to drink it.

Test #7: Conduct a Visual Check

There are several ways to test hard water. One way is to use a pH meter. This device measures the acidity or alkalinity of water. If it reads 7.0 or above, you have hard water. You can also run some tap water into a glass container and add baking soda. After about 30 minutes, take a look inside the container. If there are bubbles, the water is acidic; if no bubbles form, the water is alkaline. Another method is to fill a clean bucket halfway full of water. Add one tablespoon of vinegar and let stand overnight. In the morning, pour out the water. If there are still bubbles, the water is hard.

If you don’t want to buy a pH meter, try testing your water visually. Pour a cupful of water onto a white plate. If the water forms lumps, the water is hard; if it runs smoothly, the water is soft.

Water Hardness Scale: How to Interpret the Water Hardness Testing Results

The average American consumes about 3 gallons of water per day. This amount is enough to fill up one-gallon jug every three days. But what happens when you go to refill it? Do you use tap water? Or do you buy bottled water?

If you live in a city, chances are you probably drink tap water. However, if you live outside of a major metropolitan area, you might be buying bottled water. Either way, you’re likely consuming some form of water that contains dissolved minerals such as calcium, magnesium, sodium, potassium, chloride, sulfate, bicarbonate, carbon dioxide, nitrate, fluoride, and silica. These elements make up the “hardness” of water.

Hardness is measured in grains per gallon (gpg). There are different ways to measure hardness; however, most home testing kits measure the total dissolved solids (TDS), which includes both the ions and molecules found in water. TDS is usually expressed in milligrams per liter (mg/L).

A simple test kit is easy to find in stores and online. You simply add a few drops of distilled water into the sample cup, wait ten minutes, and read the results. A reading over 50 mg/L indicates hard water. Anything under 10 mg/L is considered soft.

There are several factors that affect the hardness of the water. First, the source of the water affects the hardness. For example, groundwater tends to be softer than surface water because it takes longer for the water to travel through soil and rock. Second, the type of mineral deposits in the water supply can increase or decrease the hardness. Third, the climate where the water originates can influence the hardness. Fourth, the age of the pipes supplying the water can change the hardness. Finally, the treatment methods used to treat the water can impact the hardness.

For example, adding chlorine to the water increases the hardness. In fact, the addition of just 0.3 ppm of free chlorine can raise the hardness by 20 mg/L. On the other hand, reverse osmosis systems tend to reduce the hardness. Reverse osmosis systems use high pressure pumps to force pure water through membranes, allowing the water to pass through while retaining impurities. As a result, the hardness decreases.

Of course, there are some things you can do to improve the quality of your water. One method is to install a water filtration system. Another option is to purchase a water purification device that uses ultraviolet light to kill bacteria and viruses.


Testing for hard water is an essential step toward keeping your plumbing system running smoothly. If you suspect that your water supply contains high levels of calcium, magnesium, iron, manganese, sodium, sulfate, chloride, nitrate, fluoride, or bromide, it’s best to consult with a professional plumber.