How Hard Is The Water In The UK?

Generally speaking, hard water is supplied to 60% of homes in the UK: especially in central, eastern and southern areas of England. Some English cities are supplied with naturally soft water from Wales and the Lake District. Water quality information, including hardness levels, for individual supplies is available from the local water supplier's customer information services. The map and notes below give indications of water hardness in the different regions of the UK.


TOTAL HARDNESS OF WATER SUPPLIES

In Scotland and Northern Ireland, various levels of hardness occur.

Scotland:
Supplies range from soft to various levels of hardness, with the majority being in the soft to moderately soft category.
Northern Ireland:
Northern Division - soft to moderately soft Eastern Division - soft to slightly hard Southern Division - soft to very hard Western division - soft to moderately hard.

Soft to moderately soft: 0-100mg/l as calcium carbonate equivalent	Slightly hard to moderately hard: 100-200mg/l as calcium carbonate equivalent	Hard to very hard: above 200mg/l as calcium carbonate equivalent

Hardness can also be measured in ppm (parts per million)
1 mg/l = 1 ppm.


Methods of measuring hardness and some equivalent values.

mg/l as calcium carbonate equivalent	mg/l of calcium	Degrees Clark or English	Degrees German	Degrees French	mg/l of sodium added during softening***
100	40	7	5.6	10	46
200	80	14	11.2	20	92
300	120	21	16.8	30	138
325	130	23	18.2	32.5	150*
400	160	28	22.4	40	194
435	174	30.5	24.4	43.5	200**

* Maximum sodium concentration in current Water Quality Regulations.
** Maximum sodium concentration permitted from 25th December 2003.
*** For total sodium concentration add the amount of sodium present in the mains water supply.