Water has been supporting countless ecosystems for billions of years and we would, quite literally, be nowhere without it. But not all water is created equal, at least when it comes to its impact on our everyday lives.

You see, water might be the giver and maintainer of life, but it can also play havoc with our appliances and our health, particularly if we don’t have a water filter or softener installed at home. What we’re talking about here is the dreaded “hard water” that leaves unpleasant residue in our kettles, stains our taps and can, in some rare cases, even make us seriously ill.

But what exactly is hard water and why is it so much more prevalent in certain areas?

What is Hard Water?

In simple terms, any body of water that contains a higher concentration of dissolved minerals, specifically calcium and magnesium, is referred to as hard water. When rainwater, which is naturally soft, passes through rock formations like limestone, chalk, or gypsum, it collects these minerals, leading to hardness. While water treatment centres can mitigate the impact of hard water, there’s only so much they can do and some of that hardness is always going to end up seeping through.

The hardness of water is measured in terms of its calcium carbonate content, usually expressed in grains per gallon or parts per million (ppm). If your water measures between 60-120 ppm, it’s moderately hard. Anything above 120 ppm is generally considered “hard”.

The Effects of Hard Water

Soap Inefficiency: Hard water can make soaps and detergents less effective. When you lather soap in hard water, it combines with the calcium and magnesium ions to form soap scum. This not only makes cleaning more challenging but can also leave residues on skin and hair, making it feel dry and look dull.

Scaling: Ever noticed a white buildup around your faucets or in your kettles? That’s scaling, caused by hard water. Over time, these scales can accumulate in pipes and appliances, reducing their efficiency and lifespan.

Laundry: Hard water can make your whites look grey and colours fade faster. The minerals can also break down fabric fibres, reducing the lifespan of clothes.

Taste and Cooking: Many people find that hard water has a distinctive taste, often described as metallic or chalky. This can affect the taste of beverages like tea and coffee. Moreover, cooking in hard water might require more time since it boils at a higher temperature.

Why is Some Water Harder and Some Softer?

The presence of hard water is directly related to the geology of an area. Regions with significant limestone, chalk, or gypsum deposits often have hard water because these rocks are rich in calcium and magnesium. Here’s a deeper look into the reasons:

Soil and Rock Composition: As mentioned earlier, regions with limestone or chalk bedrock tend to have harder water. When rainwater permeates through these rocks, it dissolves the calcium and magnesium present, which then enters the water supply.

Aquifers: In some areas, groundwater stored in natural underground reservoirs, or aquifers, has been in contact with rock for extended periods, allowing for more mineral dissolution.

Lack of Dissolved Gases: In regions where the groundwater lacks dissolved gases like carbon dioxide, calcium and magnesium carbonates tend to precipitate out of the water less, making the water harder.

Age of Water: Older water, which has been in contact with rock for a more extended period, is generally harder because it has had more time to pick up minerals.

Combatting Hard Water

Water Softeners: These devices replace calcium and magnesium ions in the water with sodium or potassium ions, softening the water and making it palatable for your home and your consumption.

Reverse Osmosis: Reverse osmosis filters use a scientific method to push water through a semipermeable membrane, removing hard minerals in the process. The vast majority of commercial water filters use this technology.

Magnetic or Electronic Water Conditioners: These devices claim to change the structure of the minerals in the water, preventing them from depositing as scale. However, their efficacy is debated, and they are prohibitively expensive.