What is Hard Water?

Hard water is common in many areas and can cause some noticeable effects around the home. Here are a few common signs that you might have hard water:

Soap Scum and Residue: Hard water doesn’t mix well with soap, so it often leaves a white or gray film on dishes, shower doors, and even on skin and hair. You might notice that soap doesn’t lather as well, and you need to use more to get a proper clean. The calcium and magnesium ions in hard water react with soap, forming a substance called “soap scum” that doesn’t dissolve. This is why soap doesn’t lather well in hard water, and it leaves a residue on skin, hair, dishes, and surfaces. This can result in dishes and glassware looking cloudy or having residue after cleaning, clothes looking dull and having a rough feel to them after cleaning, and dry skin and hair since hard water can leave soap and shampoo residue on the skin and hair, causing dryness, irritation, and buildup.

Clogged Showerheads and Faucet Aerators: Over time, hard water causes mineral buildup, clogging showerheads and faucets. This can reduce water pressure and affect the efficiency of fixtures.

Increased Soap or Detergent Usage: Hard water makes it harder for soaps and detergents to lather, so you may find yourself using more product to get a good clean.

In the longer term it can also lead to limescale deposits since hard water contains minerals like calcium and magnesium, which can leave chalky, white limescale deposits on sinks, tubs, and appliances. These deposits can also lead to water heater and appliance issues since hard water buildup in appliances like dishwashers, water heaters, and washing machines can make them less efficient, increase energy costs, and shorten their lifespan.

What makes water hard?

Hard water is water that contains a high concentration of dissolved minerals, primarily calcium and magnesium. These minerals are picked up as the water travels through soil and rock. When water has a higher level of these minerals, it becomes “hard.”

While hard water is not harmful to drink, it can be inconvenient and costly for household use due to the issues with cleaning, appliances, and plumbing.

A simple DIY test to check for water hardness is called the “soap test”. Here’s how you can do it:

What You Need:

  • A clean, transparent plastic or glass bottle with a cap (a clear water bottle works well)
  • Liquid dish soap (a pure soap without additives like moisturizers or scents is best)
  • Tap water

Steps:

  1. Fill the Bottle: Fill the bottle about one-third full with tap water.
  2. Add SoapAdd about 10 drops of liquid dish soap to the water. Make sure it’s a simple, pure soap, such as Castile soap, as additives in some soaps can interfere with the test. 
  3. Shake It: Screw on the bottle cap tightly and shake the bottle vigorously for about 10–15 seconds.
  4. Observe the Results:

    • Soft Water: If you have soft water, you should see a lot of bubbly, frothy foam at the top, and the water below should be fairly clear.

    • Hard Water: If you have hard water, you’ll see few to no bubbles, and the water will appear cloudy or milky instead of clear.

How It Works:

The minerals in hard water (like calcium and magnesium) react with soap to form a residue instead of creating lather. Soft water, with fewer minerals, will allow the soap to create a good amount of bubbles. This test gives a rough qualitative indication, but if you want a quantitative reading with more accuracy we would highly recommend our magnesium test strip. With our total hardness test and magnesium test together you can roughly calculate the level of calcium since total hardness is mostly made up of of = calcium (Ca) + magnesium (Mg).

What are the total harness units?

In the water softening industry, hardness is commonly measured in “grains per gallon” (gpg), with one gpg being roughly equivalent to 17.14 parts per million (ppm) as calcium carbonate (CaCO₃). In the aquarium industry, however, hardness is often expressed in “degrees hardness” (dH), where one dH equals approximately 17.5 ppm as CaCO₃. High hardness levels in aquariums can impact the health and breeding behaviors of fish. Our strips for aquariums that provide pH, alkalinity, and hardness all on the same test strip.