When you test your home’s water quality, one of the most common and impactful metrics you will measure is water hardness. While water hardness isn’t a concern for your health, it has massive implications for your plumbing, your appliances, your skin, and your home’s aesthetic.

This guide will explain what water hardness means, how to read your test results, and what action you should take if your water is too hard or too soft.

What is Water Hardness?

Water hardness refers to the concentration of dissolved minerals, primarily calcium and magnesium, present in your water supply.

When rain falls, the water is naturally soft. However, as water flows through the ground and filters through rocks like limestone, it naturally dissolves and collects minerals which adds hardness.

Water Hardness Scale: How to Interpret Your Test Results

Water hardness is measured either in parts per million (ppm), milligrams per liter, or grains per gallon (GPG).

PPM to GPG Conversion Calculator

Use the scale below to interpret your water test results and determine if your water is too hard, too soft, or balanced.

Water Hardness Classification Chart

• Soft Water: 0 to 60 ppm; 0 to 3.5 GPG
  • Interpretation: This water has very low mineral content. No water softening treatment is necessary. It’s important to make sure your water isn’t aggressive/corrosive.
• Moderately Hard Water: 61 to 120 ppm; 3.5 to 7 GPG
  • Interpretation: This water contains a balanced amount of minerals. It is not likely to cause damage to appliances, and a water softener may not be required.
• Hard Water: 121 to 180 ppm; 7 to 10.5 GPG
  • Interpretation: This water has elevated mineral levels. You will likely notice scale buildup, dry skin, and reduced efficiency of soaps. Water softening is highly recommended.
• Very Hard Water: Over 180 ppm; Over 10.5 GPG
  • Interpretation: This water contains high mineral concentrations. Serious scale buildup will occur in pipes and water heaters, reducing appliance lifespan. Water softening is highly recommended to prevent damage to plumbing and appliances.

What Does “Too Hard” Water Mean for You?

If your water hardness test results fall into the Hard or Very Hard categories (above 120 ppm or 7 GPG), you will likely experience these negative effects of hard water.

Scaling on Plumbing

When hard water is heated, the calcium and magnesium minerals crystallize and form limescale. Limescale builds up inside your pipes, hot water heater, dishwasher, and washing machine. This mineral buildup restricts water flow, reduces water pressure, and forces your water heater to use more energy to heat water, leading to higher utility bills.

Soap Scum

Calcium and magnesium ions react chemically with the ingredients in household soaps and detergents. Instead of lathering cleanly, the soap binds with the minerals to create a sticky, gray residue known as soap scum. Soap scum sticks to your bathtub, shower tiles, dishes, and laundry, leaving surfaces looking dull or spotted.

Dry Skin and Brittle Hair

When you bathe in hard water, the soap scum residue does not rinse clean from your skin or hair. The mineral film clogs pores, strips natural moisture, and can trigger or worsen skin conditions like eczema. Hard water also leaves hair feeling dry, brittle, and difficult to manage.

What Does “Too Soft” Water Mean for You?

While extremely hard water is a common issue, water that is artificially or naturally “too soft” (under 17.1 ppm or 1GPG) can also cause problems.

Plumbing Corrosion

Naturally soft water often has a low pH and lacks minerals. This lack of minerals makes soft water slightly acidic and aggressive. Aggressive water is more likely to leech heavy metals, like Lead, into your drinking water over time.

Difficult Soap Rinsing

While soft water lathers exceptionally well, it can make rinsing soap off your body feel difficult. Soft water leaves a slippery sensation on the skin. While this isn’t harmful, it can be annoying when showering if you are not used to the sensation.

Next Steps: How to Treat Your Water Hardness

Once you know your water hardness levels, you can choose the correct treatment option for your home.

If Your Water is Too Hard (Over 120 ppm):

• Install an Ion-Exchange Water Softener: An ion-exchange water softener is the most effective solution for hard water. This system swaps the calcium and magnesium ions in your water with sodium or potassium ions, reducing limescale buildup.
• Use a Salt-Free Water Conditioner: If you want to prevent scale buildup without using salt, a water conditioner alters the physical structure of the minerals, so they are less likely to stick to surfaces, though it does not technically lower the water’s hardness level.

If Your Water is Too Soft and Acidic (Under 60 ppm with Low pH):

• Install an Acid Neutralizer: If your soft water is actively corroding your pipes, an acid neutralizing filter can add controlled amounts of calcium carbonate back into your water. This process raises the pH, stabilizes the water, and protects your plumbing system. It is best to talk to a water filtration professional about this process and if it’s right for your situation.

Frequently Asked Questions About Water Hardness

Is hard water safe to drink?

Yes, drinking hard water is safe and does not pose a health risk. The calcium and magnesium found in hard water are essential nutrients that your body needs.

Will a filtration pitcher fix hard water?

No, standard carbon pitcher filters are designed to reduce chlorine, bad taste, and heavy metals like lead. Standard carbon filters do not remove calcium or magnesium, meaning they will not soften hard water.

How often should I test my water hardness?

If you are on city water, we recommend testing at least once a year, and part of this testing will include hardness. For well or spring water, we recommend testing at least quarterly. If you have a water softener installed, using DIY Test Strips gives you a very affordable way to test monthly to ensure the softener is working. This can cost as little as approximately $1 a month.