Water Hardness Facts.

//Water Hardness Facts.

Water Hardness Facts.

How Is Water Hardness Caused?

Water hardness is caused by a variety of dissolved metallic ions, predominantly Calcium and magnesium. These ions are naturally present in water and can reach considerably high concentrations in groundwater from limestone areas. The dissolved minerals can sometimes make the water appear cloudy when heated.

Hardness is a natural characteristic of water which can enhance its palatability. It is perfectly safe for everyone to drink and may, in fact, be good for you. Drinking hard water will increase intake of essential minerals (calcium and magnesium) and may have a protective effect against cardiovascular disease and reduce risk of high blood pressure.


Water Quality Limits

Hardness is generally expressed as mg/l CaCO3 units, although other units can be used. The following is one of several arbitrary classifications of waters by hardness:

Soft up to 50mg/l CaCO3

Moderately hard 150 – 250 mg/l CaCO3

Moderately soft 50 – 100 mg/l CaCO3

Hard 250 – 350 CaCO3

Slightly hard 100 – 150 mg/l CaCO3

Very hard over 350 mg/l CaCO3

There is no specific limit for hardness under Irish Drinking Water Regulations. However, based on limits for calcium and magnesium, a limit of 705 mg/l CaCO3 is inferred.

General Advice

When hard water is heated calcium deposits or ‘lime scale’ might form. This can affect household appliances such as kettles, dishwashers, washing machines and some heating systems. Depending on the interaction of other factors, such as pH and alkalinity, water with hardness above approximately 200 mg/l CaCO3 may cause scale deposition. So what can you do?


Kettles, Burcos Or Tea Stations

Try to boil only what you need and don’t leave the surplus boiled water lying in the kettle. Kettles can be descaled by half filling with half water / half vinegar, leaving overnight, rinsing, refill and boil water, then discard water and kettle is ready for use. Descaling kits are widely available in supermarkets.


Washing Machines

A wide range of products are commercially available (e.g. Calgon) to prevent the deposition of lime scale during the heating of water in washing machines. Varying the dosage of washing powder may also work.


Heating Systems And LPHW

Indirect heating systems where water is re-circulated are generally not affected by limescale. Direct heating systems, where fresh water replaces heated boiler water, may experience some blockage of pipes and reduced boiler efficiency. Symptoms of this would be rattling in the pipes when the water is heated, and gradually longer heating times. Consult us at http://[email protected] if such problems are suspected.



Dishwashers generally have built-in water softeners. Users should ensure these are set according to manufacturer’s instructions.


Shower Head

If limescale has built up – soak the shower head in half vinegar / half water solution for three hours or overnight to remove the limescale. Descaling kits are widely available in supermarkets.


Soften the entire Water Supply?

Chemically softened water is not suitable for everyone to drink – particularly for infants and other risk categories. For that reason it is not recommended that entire mains water supplies are softened.

Even though the hard water is perfectly safe to drink, meets all the required drinking water standards and is good for you, some people may choose to “soften” their supply.

Hard water can be “softened” by chemically removing calcium (by ion exchange) from the water and replacing it with sodium chloride or potassium chloride. Each individual household has the option of installing their own domestic water softening unit. There are no grants or funding available from central Government to assist with the installation of softening units, or the purchase of new appliances.

Softening units work by chemical, electric or magnetic processes to prevent scale deposition. The effectiveness of the units cannot be guaranteed. Care in the design and installation of softening systems is essential, in order to prevent excessively high levels of chemicals in the softened water which could be damaging to health. For this reason, if householders are considering installing water softening units such units should be designed to only soften the water sent to the domestic hot water system and leaving the cold water supply to the kitchen sink excluded from the softening process.


Water Softener Alternative

The Dropson range of descaling devices use patented electro magnetic impulse technology along with the Dropson vortex effect to fight new limescale formation as well as descaling existing limescale deposits. Contact us at http://[email protected] for more information and arrange a site report.

2016-11-22T10:58:29+00:00May 10th, 2016|General|

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