Hard Water and Why Your Plumbing Doesn't Like It

Hard Water and Why Your Plumbing Doesn’t Like It

Hard water is one of those terms you may or may not have come across before. Perhaps you’ve heard it on TV or the radio, read it online or seen it in an advertisement. Most likely, you’ve never stumbled across the term, or at the very least know very little about it.

Not to worry. Metropolitan Plumbing is here to explain the difference between hard and soft water, detail how water hardness occurs and whether you can soften it. We’ll also run through the positive and negative effects of water hardness on your plumbing and hot water systems.

So… What is Hard Water?

Hard water is overabundant in the minerals calcium and magnesium carbonates. There are various degrees of water hardness. The mineral content levels are measured in milligrams per litre (mg/L). The Australian Government-backed Cooperative Research Centre for Contamination Assessment and Remediation of the Environment classifies anything below 60 mg/L as ‘soft’ water. Mineral content between 61-120 mg/L results in moderately hard water. Between 121-180 mg/L your water is hard, while anything over the 180 mg/L count is very hard water.

Across Australia, water hardness varies greatly between the states and territories. Tasmania and Victoria boast the softest water while South Australia, Queensland and the Northern Territory claim the hardest water.

How Does Hard Water Form?

Rainwater, which is regarded as soft water, falls from the sky and soaks into the ground. As it makes its way through the earth, it permeates limestone rocks and chalk deposits in the ground.

The water dissolves and accumulates some of the minerals, becoming hard. Areas with a higher concentration of chalk and limestone (and even gypsum) will typically have harder local water supplies than areas that are less concentrated in dissolved minerals.

Is Hard Water Safe As Drinking Water?

This question deserves more than just a black or white, yes or no answer. Basically, there are advantages and disadvantages to hard water. It’s really up to you whether or not you think drinking hard water is safe.

The biggest upside to consuming high concentrations of calcium and magnesium-rich hard water is simply that you’re getting a higher intake of calcium and magnesium. It may not fulfil your recommended daily intake requirements, but both are essential nutrients for the human body.

Calcium is vital for healthy bones and teeth and is also instrumental in aiding blood clotting, muscle contraction, heart rhythm regulation and nerve function management. Magnesium intake is equally as crucial.

Health Direct outlines magnesium as being an important factor in maintaining healthy blood sugar levels, healthy muscles, nerves and bones, and minimising the risk of developing high blood pressure, type 2 diabetes, osteoporosis and other health concerns. All are valid and worthy ticks on the plus side of drinking hard water.

Man collects water from a tap in his water bottle.

Negative Effects of Water Hardness

Unfortunately, there is the other side of the argument. Mineral deposits in hard water have been linked to the development of kidney stones and can dry out skin and hair.

Aside from the potential health benefits described above, there are few additional advantages to consuming or using hard water in your home. If anything, it’s more likely that hard water will do no favours for your plumbing or your plumbing. We’ve outlined the most common negative effects.

Build-up of Limescale in Essential Plumbing Fixtures

Boiling hard water can result in the formation of limescale, a combination of calcium carbonate ions. It’s a process called ‘scaling’ and occurs in your kettle, the bathroom shower head or the hot water system. As the limescale builds up, it covers any surface it touches. This can lead to unsightly deposits on and around taps and other fixtures. These deposits not only age your plumbing fixtures, but built up limescale can affect the water pressure. With your hot water system, limescale deposits can reduce its performance too, requiring you to use more energy for better heating and thus drive up your energy bills. In short, limescale, caused by hard water, is the enemy of plumbing.

Hard Water is Harder to Lather Than Soft Water

Whether you’re washing the dishes or washing yourself, you’ll find that hard water doesn’t lather up quite as well as soft water. This is because of a chemical reaction that occurs between the minerals in the water and the ingredients in soap that effectively neutralises its lathering properties. To improve washing ability, you’ll need to use more dishwashing liquid, soap or body wash than normal.

It Leaves Behind White Spots and Stains

You will often find white spots on items around the house that come into regular contact with water. Glassware, shower screens, kettles and even car windows will still have white spots despite being properly cleaned and rinsed. This is because once the water has naturally evaporated, the traces of dissolved calcium and magnesium concentrations remain. Soap scum can also be a factor in this.

Sinks and Bathtubs Become Stained

You might clean your kitchen sink, shower screen or bathtub until the surfaces are sparkling, but if you’re washing with hard water, the return of unwanted surface stains is a sure-fire guarantee. Frustrating, isn’t it? Like the previous example, the minerals in the hard water stay behind once the water itself evaporates, leading to unsightly stains.

Generally, most of these are relatively easy to combat. For example, you can use natural remedies such as water and lemon juice or lemon and household vinegar to clean up limescale in your kitchen kettle. For bathtub and toilet stains, create a paste using baking soda and white vinegar. Apply that to any surface needing cleaning, then wipe it off about 30 minutes later with a dry cloth (microfibre works best). If natural products don’t work, then you may need to consider a chemical cleaner.

Hard water can stain baths, glass and more.

How to Soften Hard Water

If you live in an area that might have water on the harder end of the spectrum, you might be wondering what you can do. Thankfully, there are some effective water softening methods you can try for household use!

Ion exchange

The oldest and arguably the most common way to soften hard water is a process called ‘ion exchange’. This involves trading two sodium ions for one of each calcium and magnesium ion using a brine (i.e. salt water) solution. This scientific exchange effectively releases the magnesium and calcium ions from the water, rendering it soft. You can purchase a water softener for your home that carries out the ion exchange process so you can enjoy softer running water throughout your home. Installing a water softener is relatively easy, but of course you can contact a plumber to do it for you.

Reverse osmosis

Reverse osmosis is highly effective in both softening water and purifying it. This multi-stage process isolates calcium and magnesium ions from the water by using pressure to push water molecules through a semi-pervious membrane. You then keep any useable soft water for storage or direct it to its intended immediate use. Excess, unwanted water – and the impurities collected by the reverse osmosis process – get redirected to the drainage system.


Distillation involves heating water in a container, allowing it to vaporise. For small quantities of soft water it’s a highly effective method. The process involves directing the water vapours towards a separate container through a cooling tube. Condensation occurs, changing the vapours back to its liquefied state. It returns to water in a soft form, free of any unwanted minerals and impurities.

Hard Or Soft Water…

Mineral-rich hard water does boast some health benefits. However, almost any experienced plumber will tell you it’s unlikely to do your home any favours. Limescale build up could block your pipes while hot water system deposits will leave you with an underperforming unit.

If hard water has negatively affected your plumbing, a call to Metropolitan Plumbing might be your best course of action! Our local experts can assess the current state of your plumbing and determine whether a repair, replacement or just a simple clean up will extend the lifespan of your plumbing. We will ensure you have high quality water flowing throughout all your fixtures and fittings.

Published: 2022-06-29

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