Water Hardness

Taste, appearance & smell

Due to the higher mineral content, hard water typically tastes nicer than soft water. Hard water looks the same as soft water, however when heated, it forms a white calcium deposit known as lime scale. You may notice a build up of limescale on the inside of your kettle or as a visible coating on the surface of a hot drink (e.g. tea). Hard water has no smell. If your water has an unusual taste or smell please visit our dedicated page on this issue.

How hard water is formed

Rain water is ‘soft water’ and normally contains very low levels of minerals. When rain falls, it seeps into the ground and comes into contact with soil and rock. If minerals like calcium and magnesium are in the soil and rock they absorb into the water. It then becomes hard water.

How hard water gets to your tap

Water hardness levels vary across regions in Ireland, depending on the soil and rock types. Hard water is often present in the rivers and lakes we use to source our drinking water. When we abstract and treat this water to make it safe to drink we do not remove the minerals, as they pose no health risks.

Why Irish Water does not soften hard water

There are good reasons why we don't chemically soften hard water.

There are no health risks involved in drinking and using hard water
Softening water removes beneficial minerals from hard water
There is no legislative requirement to remove hardness from drinking water
Depending on the technology used, artificially softened water may not be suitable for everyone to drink, e.g. increased Sodium levels caused by salt softening may not be suitable for infants or at-risk groups
Hard water can create an internal protective film on lead pipes or fittings. This can prevent metals such as lead leaching into your drinking water supply. To find out more about the dangers of lead in drinking water visit our dedicated information section.

Limescale - how to treat and prevent it

Limescale is formed when you heat hard water. It can form a coating or fur within your kitchen appliances and heating system. It may also reduce the effectiveness of detergents and/or soap.

Here are some tips to treat and prevent limescale build up in your hot water appliances and systems. Remember to always follow the manufacturer’s instructions for any of your appliances that use water.

Kettles or other drinking water boilers

Place a stainless steel wire scale collector in your kettle.
Rinse plastic kettles regularly if there is limescale floating on the water surface.
Do not leave leftover boiled water sitting in the kettle.
Regularly descale your kettle – consult your local hardware store for advice

Hot water heating systems

Heating systems that recirculate the same water within a closed loop are generally not affected by limescale formation. However if you have a heating system where fresh water can replenish any water lost from the system, limescale may build up over time and reduce the efficiency of your heating system. This may become evident through your heating pipes starting to rattle or your radiators taking longer than usual to heat. If you are concerned you should consult a plumber to examine your heating system.
Reducing the temperature set point of your water heater may reduce the level of limescale formation.

Washing machines, dishwashers and hard water

Dishwashers often have built-in water softeners. These should be used according to the manufacturer’s instructions.
You can use water-softening products in your washing machine to help prevent limescale build-up.

Install a softening unit

If you find hard water is a problem in your home you can install a domestic softening unit. Irish Water cannot recommend any particular unit or guarantee its effectiveness. It is best to talk to your local plumber for advice in this area.

Further information

For more information visit the World Health Organisation (WHO) website

Concerned about the quality of your drinking water?
Contact us on Callsave 1850 278 278. Lines open 24 hours a day, 7 days a week.