What is Hard Water and Why It’s Harmful?

how to measure the hard waterWater is the most important and useful, naturally occurring substances in the world. Without water, the survival of any living thing is impossible. On the other hand, impure water can be harmful not only to humans but other living things as well. Today, we are going to discuss hard water in this article and how it can be harmful.

What is Hard Water?

USGS, science for a changing world, defines hard water as water, which has high amounts of dissolved minerals, primarily calcium and magnesium. Water hardness is defined as a measure of the quantity of calcium and magnesium in water. In general terms, hard water can be described as water that leaves slime and scale build-up on your water-using devices, showers, and faucets. Hard water also makes the glass crockery less clear, and it becomes cloudy. You may even notice your hands get slimy if you wash them with soap and hard water.

Measuring Water Hardness

Hardness is caused by the presence of calcium and magnesium compounds and some other metals as well. These other metals are not included while measuring the hardness of the water. A general classification of the water hardness is explained below according to the level of calcium carbonate in your water. The quantity of calcium carbonate is measured in mg/L (milligrams per liter) or grains per gallon.

Category Amount in mg/L Amount in grains/gal
Soft Water 0 – 17 0-1
Slightly Hard 17.1 – 60 1-3.5
Moderately Hard 61 – 120 3.5-7.0
Hard 121 – 180 7.0-10.5
Very Hard More than 180 10.5 and above

It has been observed that water sources that use underground water supply are harder as compared to other sources. The reason is that when water moves through soil and rock, it dissolves small amounts of calcium and magnesium and other hardness causing elements. People using well water as the primary source of water in their home must use water softeners to reduce the hardness of the water.

Water Hardness in the United States

The last assessment of water hardness in the US was made in 1975. This data is very old, but it is being used to check the hardness of water by authorities and suggest suitable measures to deal with the problem of hard water. The following map illustrates the hardness in the US.

Why is Hard water Harmful?

hard water and plumbing issues

Slightly hard and moderately hard water are not harmful to human beings. Our body needs these minerals in minute amounts. The problem arises when we drink hard or very hard water for a very long time. The presence of a high amount of calcium and magnesium can cause stomach problems, blood pressure issues in our body. It can also disturb the overall internal balance of our body and can impact the working of certain organs like the liver and kidneys. Bathing in hard water can cause skin problems and hair problems as well. Apart from its impact on the human body, hard water has the following disadvantages as well:

Reduced Life of Electronics: All the water-using appliances are sensitive to hard water. If your area has hard water, you will notice a scale build-up on your devices like washing machines, coffee makers, and dishwashers.

Plumbing Problems: Hard water reduces the life of plumbing fixtures in your home. Plumbing pipes become weak over time when hard water passes through them with a high percentage of calcium and magnesium carbonates. You will also notice a white scale build-up on your showers, faucets, and other taps in your home.

Also see: 7 Quickest Ways to Get Rid of Hard Water Stains


Hard water must not be left untreated. Drinking hard water in large quantities can negatively impact our health. Most of us ignore the hard water problem by just cleaning our appliances once in a while. We ignore the fact that hard water can reduce the working efficiency and overall life of our appliances.

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