What Water To Use In a Steam Iron 

By  Enda McLarnon

Aside from ironing board covers, and cleaning a steam iron, the next question we are asked the most is, "What is the best 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 for what is the best water to use in a steam iron is to use 50% tap water and 50% distilled water.

Please note distilled water is also mistakenly 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.

Distilled Water - 5.5 Litres - Ultra Pure Water

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  distilled 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.

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Price when reviewed £13.95

Where Do Home Water Supplies Come From?

In the United Kingdom, most homes are served from what is called a main's water supply.

A small percentage may get supplied from a well, but the vast majority turn on their water taps, and the water that comes out is channeled through pipes under the ground and into our homes.

  • 70% of all water supplied comes from man made reservoirs
  • 30% of all water supplied comes from ground water

This water then goes through water treatment plants and the regulations that cover the standards are currently an EU Directive known as "The Drinking Water Directive (98/83/EC), which specifies water quality.

In simple terms these are the standards that makes drinking water safe to drink. (These will still apply after Brexit)

Understanding Tap Water

In all of our homes we use tap water for drinking and also for washing. The standard of water in the UK is very high and is safe to both wash and bathe in. It does however sill contain minerals and impurities even after it has been treated in the water treatment plants.

For example chlorine is a disinfectant used by water companies to maintain hygienic conditions within the public water supply network of pipes. The levels are low 0.5 mg/l or less, but that is an example of an impurity

Can You Use Tap Water in a Steam Iron?

The simple answer to this is yes you can. For the huge majority of homes throughout the UK, putting tap water into your iron is the most common thing to do. The only real issue is what is called hard water areas which we explain below.

The standard of tap water in the UK is extremely high, and there are legal obligations on water companies that ensure this high standard is achieved and maintained. It is good enough for babies, toddlers, children and adults.

Why Do Some Steam Iron Manufacturers Recommend Using 50% Tap Water and 50% Distilled Water?

This is where the confusion about which type of water to use in a steam iron starts to happen. Quite a few manufacturers state in their instructions that you should use a half and half mix of tap and distilled water.

They offer this advice for two reasons:

  1. They sell these ironing products throughout the world and water quality varies a lot - they however only print one set of general advice and instructions
  2. The second reason is limescale build up especially in areas with hard water

On the first point above, you will be aware if you travel in Europe or some other parts of the world, that you simply would not risk drinking their water straight from the tap. That is why many homes there buy and use bottled water.

We don't have that problem in the UK, but some people still prefer bottled water. However manufacturers sell their irons around the world and that is why they recommend using a mix of water to help lower the impurity rate of the water in these countries. It really does not apply in the UK.

Water Hardness In the UK

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.

We 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.

Hard Water and Limescale

The second point above about hard water is more relevant for the majority of county areas in the United Kingdom. Some areas of the UK have what is called "hard water." Hard water has a high mineral content. This type of water initially flows from ground that has large deposits of limestone and chalk. Those deposits primarily consist of calcium and magnesium carbonates and bicarbonates.

Around 60% of the UK is classed as having hard or very hard water. If you have ever noticed a white scale building up at the bottom of your kettle or iron, then this is called limescale.

In terms of drinking this water, you actually get the benefit of calcium in your diet so no bad thing, When it comes to water pipes, boilers and electrical appliances, limescale is not a good thing.

The water in the UK is treated to some of the highest standards in the world. Rain falls in the UK (as we are 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.

The Real Cost of Hard Water

Most people are unaware of the real cost of using hard water in electrical appliances. In fact hard water can lead to:

  • Higher than necessary energy bills
  • Appliance maintenance or replacement
  • Having to buy cleaning products

Where Does Limescale Come From?

As we mentioned earlier limescale 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 when heat is applied.

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)

What Products Are Affected by Limescale Build Up?

The main areas of your home that can be impacted by limescale include:

  • Pipes and boilers
  • Electrical water heaters including kettles and hot water dispensers
  • Showers and taps
  • Washing machines
  • Steam Irons, steam generator irons, steam presses and garment steamers

How Does Limescale Affect Your Steam Iron?

All steam irons, steam generator irons, presses and garment steamers have a boiler that heats the water. So if you live in a hard water area and you add tap water to your iron, that water is inside a small metal boiler.

An element within your iron heats that water. Various small chemical reactions take place between the minerals in the water and the heating element.

Over time that chemical interaction leaves a very thin scale of lime. Those layers then build up over time and get thicker.

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.
Enda McLarnon owner of the Steam Gen Reviews UK website

Enda McLarnon

I hope that you find my How to articles helpful as I know that laundry can be a real chore. On this website, I have tried to help out with buying guides and reviews for the many forms of ironing and other laundry issues.

Enda McLArnon

We have chosen products we think you will really like and may earn a commission from links on this page. Read about why you can trust our reviews and recommendations.

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  1. Distilled water is different to deionised water, they are produced by different processes and as a result are completely different forms of water. Distilled water is the purest form and more costly. Please Google “difference between…”

  2. The article was very helpful. We have just had a water softener installed and I was wondering if I had to continue to buy distilled water. I also didn't know about 50/50 tap water to distilled. Thank you.

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January 30, 2024

Believe it or not one of the most

January 30, 2024

If you have ever wondered how to iron

September 16, 2023

In this article we explain how to wash

July 28, 2017

It is a fact of life that most