We often get enquiries about limescale in water so we wanted to explain what it is, why it’s there and why it’s really difficult for us to reduce it in our supplies. Our Head of Water Quality, Clair Dunn, explains in this blog post.
Limescale is caused by minerals such as calcium and magnesium in water and it’s this that makes our water hard. In fact ours is one of the hardest water regions in the UK. The minerals are present because of the geology of the landscape in the east of England. The ground contains rocks with a high chalk (calcium carbonate) content and this dissolves as water moves through it.
Hard water is not harmful to us in any way – in fact there is a lot of evidence that these minerals are good for our bodies, in particular our bones – so there is no health reason to reduce water hardness. There are other benefits to hard water – it helps us get clean quicker in the shower because it doesn’t produce lots of lather, and brewers say it makes better beer!
But there are also problems with it. It can produce scum on the top of a cup of tea (because minerals react with tannin in the tea), and, of course, it can scale up kettles and other appliances. There are things that can help, such as stainless steel products which are put in the kettle to collect the limescale – and there are water softener devices you can get installed in your home.
But why doesn’t Anglian Water soften the water before it gets to your taps? Well, firstly not all customers want their water softened. But, crucially, water softening on a large scale is a very expensive and energy-consuming process and carrying it out at all our treatment works would put everyone’s water bills up considerably. Softening processes such as this would only reduce the hardness slightly, not producing the soft water that other regions have.
Another factor is that the process of softening water can involve replacing calcium and magnesium with sodium – this can cause issues for some people who are on low-sodium diets for medical reasons.
Water is a local product – for almost all of us the water we drink comes from a source less than 100 miles from our home, and for most it is much closer. So our hard water is simply the result of where we live in the UK. However there are many things we can, and do, treat out of water to ensure our water it is safe and healthy to drink. In fact our region’s, and the UK’s, water is some of the safest in the world. Our team of samplers and scientists carry out thousands of regulatory tests a week on water supplies, and we pass more than 99.97% of them.