What Water To Use In a Steam Iron?

Aside from ironing board covers, and cleaning a steam iron, the next question we are asked the most is, "What Water To Use In a Steam Iron?" In this article we will answer this question.

Quick Answer

  • For those in a hurry the quick answer is to use 50% tap water and 50% distilled water. 

Please note distilled water is also called De-Ionised water.

A few years back every single iron manufacturer recommended only distilled water, but that caused other problems. As the water was so pure it actually could cause some irons to split at the joints or seams, and they would then start to leak.

These days, almost every single iron manufacturer recommends this half and half split of distilled and ordinary tap water. It is always advisable to read the instruction manual for the individual iron that you have bought.

In there you will find their recommendation which you should follow, as to do otherwise will likely invalidate the warranty.

Why Does the Water Make Any Difference to the Iron?

Most people in the UK will be familiar with what is called limescale. This is a chalky crust that you will find inside irons,kettles and radiators in central heating systems. 

This is called calcium carbonate and it is a chemical compound. This compound is left behind when hot water evaporates. Over time it can build up and form a hard crust that is hard to remove.

It causes staining and over time it will damage the component parts of a steam iron, garment press, steamer or a kettle.

The distilled water shown to the left is typically what many iron users put into their steam iron.

They mix 50% of their normal tap water along with 50% of this top up De-Ionised water if they live in what is classed a "hard water area."

This helps a lot in preventing the build up of limescale in the bottom of any appliance such as a garment press, kettle or iron.

Where Does Limescale Come From?

As I mentioned earlier it is a chemical reaction that happens when the hot water evaporates. The water inside your appliance contains chemicals, and these react with the minerals in the water.

If you remember back to your school days you likely learned about the different types of water in some type of Science class. (Assuming you were paying attention as it is not the most thrilling subject)

In the United Kingdom there are many different water supplies and most of them go through some type of water plant treatment. Depending on the source of the water it will be classed from either very soft and all the way through to very hard.

I will not bore you with the many minerals as the important one to know about is calcium. It is this which causes limescale and is very common in hard water areas.

About 13 million homes in the UK have a hard water supply, in other words the water contains lots of calcium, and will cause limescale to build up quicker in a steam iron if not controlled.

By mixing distilled water and your tap water, you help reduce the amount of calcium.

Top Tips to Reduce Limescale

There are a couple of things you can do to reduce the amount of limescale:

  1. Use a 50/50 mix of distilled water and tap water
  2. Empty the iron completely when you are finished to prevent it just sitting in the water tank of your iron
  3. Most modern irons have some from of de-calc on them, so use that regularly as it helps to extend the life of your iron
  4. Many irons also use filters and it is always advisable to change those according to the manufacturer's instructions.

Water Hardness In the UK

The water in the UK is treated to some of the highest standards in the world. Rain falls in the UK (as I am sure you know) and then seeps through the ground.

It can either remain soft or attain a certain level of hardness depending on what it passes through. For example in areas where there is hard rock like granite the water will be soft. That is because the rain can not get through the hard rock.

On the other hand if the rain lands on ground such as chalk or limestone which are soft rocks, the water picks up minerals like calcium and magnesium, and these get into the water supply. That means you get hard water and that always means more limescale.

England Hard Water Counties

  • Bedfordshire​​​​
  • Berkshire
  • Buckinghamshire
  • Cambridgeshire
  • Dorset
  • Essex
  • Gloucestershire
  • Greater London
  • Hampshire
  • Hertfordshire
  • Kent
  • Oxfordshire
  • Surrey
  • Sussex
  • Wiltshire


Scotland has mainly got soft water thanks to the deposits of hard rock.


Wales water is mainly soft or soft to moderate

Northern Ireland

Northern Ireland mainly has soft water with a few exceptions where it is hard. These include:

Parts of County Fermanagh, the County Down Coast and around Lough Neagh.

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