Water Hardness

Drinking water in England and Wales is of a very high quality but some people are concerned
about whether they have hard water. This information answers the questions most often asked about hard water.

What causes hard water?

Water that is hard contains calcium and magnesium compounds.

Rain water is naturally soft, it does not contain any minerals, but as it seeps through the ground it can pick up minerals, such as calcium and magnesium compounds, from the soil and rocks it passes through. If rain water passes through soft rocks like chalk or limestone, it picks up these minerals. If it passes through granite of through peaty soils, it does not pick up these mineral and so remains soft.

What are the problems with hard water?

Hard water causes pipes to fur up and scale to collect in kettles and in electric irons and washing machines. If the scale collects on heating elements if shortens their life and makes appliances less efficient. It is also more difficult to work up a lather from soap, washing up liquid and washing powders. It can also cause “tide marks” on basins, sinks, baths and toilets.

How can I find out if I have hard water?

The map overleaf shows generally hard and soft water areas. The map is only an indication because even hard water areas can contain pockets of soft water and vice versa. You can get detailed information from your water company. Enquiry numbers are listed under WATER in your telephone directory.

Is there a standard for the hardness of drinking water?

There is no maximum value for total hardness of water supplies. There are maximum values for two substances, calcium and magnesium, which cause hard water. In England and Wales all water supplies meet the value for calcium and six supplies exceed marginally the value for magnesium, but as there is no risk to health, a relaxation of the magnesium value has been granted by the Inspectorate for these supplies. Where water companies soften water before they put it into the supply, there is a minimum value for total hardness which all the softened supplies meet.

Should I use a water softener?

This is a matter of personal choice. A softener will improve the efficiency and increase the life of appliances using hot water. It will make lathering easier and reduce tide marks on sanitary ware. Some people with skin conditions, such as eczema, have fewer problems if they use soft water for washing. But if you do install a water softner you should make sure that you have a supply of un-softened water for drinking and cooking.

This is because:

- There is evidence of less heart disease in hard water areas than in soft water areas, although not all studies find this link. If something in hard water protects against heart disease, water softeners might remove this protection along with the hardness.
- Many water softeners work by replacing the hardness with sodium. Too much sodium can be a problem for premature babies because their kidneys are not good at filtering it out of the blood, and for people who are low on sodium (low salt diet).
- Soft water may release lead from any lead pipes downstream from the softener.

If you do decide to have a water softener we advise that you buy it from a reputable supplier, for example, one which is a member of British Water (information service 0181 878 8618), and have it installed by a qualified plumber who is a member of a recognised Trade Association, such as the Institue of Plumbing. We also advise that you maintain it in accordance with the suppliers instructions.

Magnetic and Electrical conditioning devices

Some of these devices have been shown to be effective in reducing the amount of fur or scale that actually sticks to pipes or heating elements. They do not soften water. However, not all products on the market give satisfactory performance. You are not advised not to buy one of these devices unless the supplier will agree to a sale or return, subject to satisfactory performance.

Click to locate your supply zone

OST 30/01/06