Water Hardness Scale: Know Your Water Quality

Soap won’t lather, your glasses have white spots, or your hair feels dry after a shower, all because of hard water. The hardness level of your water is what’s messing things up.

Check out this water hardness scale to see what your water might be like.

You can check your water hardness level using home test kits or by sending a sample to a lab. NJ Water Systems even offers free water testing, so you can get a report that shows how hard your water is and any other stuff you might want to know.

Understanding the Water Hardness Scale

Do you see those white, flimsy spots on your dishes? They came from hard water. The yellow buildup around the sink is also a byproduct of hardness. 

It is a common water problem in households. Residents in NJ are dealing with such issues daily. But what are those? What is the hardness in water? 

Hard water happens when minerals like calcium and magnesium build up in your water supply. When that happens, you end up with hard water. You use it for drinking and washing your clothes and dishes, which can cause all sorts of issues.

But how do we measure how hard or soft our water is? That’s where the water hardness scale comes in!

How is Water Hardness Measured?

Water hardness is typically measured in two units:

1. Grains per Gallon (GPG): This is one of the most common measurements in the U.S. One grain per gallon equals about 64.8 milligrams of calcium carbonate per litre of water.
2. Parts per Million (ppm) or Milligrams per Liter (mg/L) – These units are often used interchangeably. I show the amount of dissolved minerals in the water. 1 GPG is roughly equal to 17.1 ppm.

You can easily check your water hardness with testing strips. If you want something more hands-on, you can use titration kits and electronic meters. 

But if that sounds too tricky, just ask your local water supplier for help. Another option is to hire a professional to do the testing for you, and they’ll give you a detailed report on the results.

Water Hardness Classification

Here’s a simple breakdown of water hardness levels:

Relatable Reads: 5 Best Water Filters for Hard Water 2025 (Tasted & Reviewed)

Why Does Water Hardness Matter?

Hard water isn’t necessarily bad for your health. It can come out as surprising, but some people like the minerals water contains.  However, it can be a nuisance in your home. 

It can cause:

• Soap and detergent inefficiency: You’ll need more soap to get the same lather.
• Scale buildup: Hard water leaves mineral buildup in pipes, water heaters, and appliances.
• Dry skin and hair: Hard water takes out all the moisture from your skin and hair. It makes you feel dry and rough.
• Spotted dishes and glassware: Those pesky white spots on glasses after washing? That’s hard water at work!

Causes of Water Hardness

Water can be hard for a few reasons. Hardness mainly comes from calcium and magnesium. When water moves through dirt and rocks, it picks up minerals along the way. 

The amount of these minerals can really vary depending on where you are. That’s why you notice different levels of water hardness in different places.

We have two main causes of water hardness:

Natural Mineral Dissolution

Water is often called the universal solvent. It means substances may dissolve as they move through the environment. 

When the rainwater falls, it softens the minerals and makes them easy to dissolve. However, as it travels through soil, rocks, and underground aquifers, it absorbs minerals from its surroundings.

Key Minerals That Cause Hardness:

• Calcium (Ca²⁺): Comes from limestone, gypsum, and chalk deposits.
• Magnesium (Mg²⁺): Found in dolomite and other rock formations.

How It Happens:

• Rainwater infiltrates the ground. It comes into contact with limestone, dolomite, and other mineral-rich rocks.
• Minerals dissolve into the water through a process called chemical weathering.
• Groundwater or surface water carries these dissolved minerals.

The longer water stays with mineral-rich rocks, the harder it gets. That’s why well water and deep groundwater usually have higher hardness levels compared to water from lakes or rivers.

Geographical Variations in Water Hardness

Not all regions have the same water hardness. 

The local geology has its part in the mineral content of water.

Regions with Hard Water

Areas rich in limestone, chalk, or gypsum tend to have hard water. These rocks release high amounts of calcium and magnesium when in contact with water. 

[Source: Water Resources Mission Area | U.S. Geological Survey]

Even within the same country, water hardness can vary dramatically. It all depends on the local geology. 

Some cities with river-based water supplies may have softer water. Meanwhile, nearby rural areas using well water may experience higher difficulty levels.

Why Does This Matter?

Knowing why your water is hard can really help you figure out if you need a water softener. If you're in an area with hard water, you might notice:

• More soap and detergent use
• Scale buildup on faucets and appliances
• Dry hair and skin
• Shorter lifespan for water heaters and plumbing

How to Measure Water Hardness?

Water hardness measurement tells you the concentration of minerals in your water. Measuring hard water is easier than you think! You can do it with a quick DIY test or a detailed lab analysis by professionals. 

Let’s look at several ways to check your water’s mineral content. 

Home Testing Kits

Home test kits are your best bet for fast and simple measures. 

These kits are affordable, easy to use, and available at most hardware stores or online.

Types of Home Test Kits

A. Test Strips (Most Common)

How It Works: Dip a test strip into a glass of water. These strips are coated with chemicals that only react when they come into contact with a mineral. Now, wait a few seconds. After a while, it will change colour, and then you can compare it to the provided chart.

B. Liquid Test Kits (Titration-Based)

How It Works: This test quickly and accurately analyses water hardness. Add a few drops of a special reagent to your water sample. These reagents detect different hardness ranges. The water will change colour based on its hardness level.

Laboratory Testing

For precise and detailed water hardness analysis. 

Lab analysis comes up with the exact concentration of minerals in your water. 

Methods Used in Labs:

Titration Method (Most Reliable)

How It Works: A chemical reagent (like EDTA) is added to a water sample.  Wait for a few minutes until it reacts completely with the calcium and magnesium ions. The amount of reagent used determines the hardness level.

Accuracy: Highly accurate, used by water treatment facilities.

Atomic Absorption Spectroscopy (AAS)

How It Works: This advanced method uses light absorption to measure calcium and magnesium concentrations. It will bring out the specific metal atoms in a liquid sample to measure water hardness. 

Accuracy: Extremely precise but mostly used for industrial purposes.

Online Resources

You can use online resources to get a quick estimate of your area's water hardness. You can even hire people to check the water hardness of your home without any hassles. 

• Here, you can do a free water test for a detailed water analysis!

Where to Check?

• USGS Water Hardness Map: The U.S. Geological Survey provides a general hardness map for the U.S.
• Local Water Utility Websites: Most city water providers publish annual water reports.
• Online Hardness Calculators: You can visit a website and enter your ZIP code to check typical hardness levels in your area. 

Check out How to Find Out If You Have Hard Water? - Signs & Tests

Impact of Hard Water on Daily Life

Hard water isn’t just a minor inconvenience. It can affect your home, your cleaning routine, and even your skin and hair. 

With each passing day, it is getting out of hand. So, it is time to take the right steps to manage it.

Household Appliances: Shorter Lifespan & Reduced Efficiency

Hard water leaves behind mineral deposits (scale) inside appliances. It reduces efficiency and increases energy costs.

• Water Heaters: Just 1/16 inch of scale buildup can reduce heating efficiency by 12%. Basically, shortens the unit’s lifespan.
• Dishwashers & Washing Machines: Hard water reduces appliance life by up to 50%.
• Pipes & Faucets: Scale buildup clogs pipes, leading to low water pressure. It just increases the cost of plumbing issues.

💡 Solution: Water softeners can extend appliance life. It is an effective solution for hard water. 30% of people in the USA are already using water softeners. 

Cleaning Challenges: Soap Scum & Increased Detergent Usage

Hard water makes it harder for soap to lather.  You start to suffer from soap scum buildup and higher cleaning costs.

• 4 times more soap and detergent is needed to achieve the same cleaning power as soft water.
• Soap scum builds up on showers, sinks, and glass. It requires more frequent scrubbing.
• Laundry washed in hard water can feel stiff and dull due to trapped minerals.

💡 Solution: Using a water softener helps improve cleaning efficiency. It will take 30% less detergent to wash clothes. 

Personal Care: Dry Skin & Dull Hair

Hard water takes away the natural moisture from the skin and hair. It causes:

• Dry, itchy skin: This worsens eczema and causes irritation.
• Dull, lifeless hair: Make hair rough, dry, and hard to manage.
• Residue buildup: This prevents shampoo from rinsing thoroughly. It leaves you with greasy roots and a flaky scalp.

💡 Solution: Use a clarifying shampoo or moisturizing skincare or install a shower filter.

Relatable Reads: Hard Water vs Soft Water: Are You Damaging Your Home?

Health Implications

Hard water can affect your health as well. Minerals like calcium and magnesium can cause skin conditions like eczema. 

1. Mineral Intake

Hard water naturally contains calcium and magnesium. Both of these minerals are essential for bone health, muscle function, and heart health.

• Calcium: Water can provide 5–20% of daily calcium needs. This may be beneficial for bone strength and for preventing osteoporosis.
• Magnesium: Some regions with hard water supply daily magnesium needs. It supports muscle function, nerve health, and heart regulation.

💡 Takeaway: Hard water can be a minor but helpful source of minerals for most people. However, those with kidney disease may need to limit their intake.

2. Potential Skin Conditions

While hard water is safe to drink, it can worsen skin conditions. It is harmful to people with sensitive skin.

• Eczema Risk: Kids living in places with hard water are more likely to get eczema because the minerals in the water can irritate their skin.
• Disrupts Skin Barrier: Hard water removes natural oils. It makes the skin dry, itchy, and inflamed.
• Soap Residue Buildup: Soap residue can leave a film on the skin. Later, it can clog pores and worsen conditions like acne.

💡 Takeaway: Installing a water softener or using a shower filter can help reduce skin irritation.

Relatable Reads: Can Hard Water Cause Hair Loss?

Solutions to Hard Water Problems

There is good news! 

A water softener is the most reliable way to tackle hard water. It will soften your water and reduce the impact of hard water on your home and health.

Water Softeners: The Most Effective Solution

Water softener uses an ion exchange system. This uses an ion exchange system that swaps calcium (Ca²⁺) and magnesium (Mg²⁺) with sodium (Na⁺) or potassium (K⁺) ions. It makes the water softer and drinkable. 

How It Works:

• Hard water enters a tank filled with resin beads
• Resin beads are coated with sodium or potassium ions
• The resin beads attract and trap the calcium and magnesium
• Replace the minerals with sodium or potassium
• Softened water flows out into your home
• The system periodically flushes out the captured minerals

Pros & Cons of Water Softeners

✅ Best for: Whole-house water softening. 

Frequently Asked Questions

What does water hardness tell us about water quality?

Water hardness shows us the mineral content, primarily calcium and magnesium.

How much hardness in water is good?

You can go for moderate hardness (60–120 ppm or 3.5–7 gpg). It provides beneficial minerals without excessive scaling.

How do you know your water hardness level?

You can test water hardness using home test strips, digital meters, or lab tests.

What is the normal hardness of water in safe water?

Safe drinking water typically falls within 60–120 ppm (3.5–7 gpg).