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The degree of severity of water hardness can vary, depending on where you live and the amount of hard scale minerals present in your water supply. 60% of UK households are in hard water areas. If you are suffering from problems with hard scale, you will probably recognise some of these tell tale signs:

  • Furring of water using household appliances like washing machines, dishwashers, showers and kettles.
  • Drinking water with poor taste, smell, discolouration or sediment.
  • Scum and scale around taps, baths, showers and sinks.
  • Scale deposits in your heating system.
  • Noisy central heating boilers and radiators with reduced flow and efficiency.
  • Soaps, cleansers and shampoos that don’t produce lather and bubbles.
  • Dull, flat, lifeless laundry.
  • Streaking and spotting of household glass and ceramics.

Measuring water hardness?

If you are unsure of the level of hardness of your water supply, your local water authority may give general guidance on levels of water hardness in your area.

You can also measure water hardness using our CalTest Water Hardness Testing Kit (Product Code: WS-WHTK).

CalTest is an inexpensive way of getting an instant reading of your water hardness. Simply add drops of water to the special reagent formula until the colour changes to greenish blue, then multiply the drops added by 20 for your water hardness measurement. E.g. 8 drops x 20 = 160 ppm (parts per million).

Hard water treatment is recommended for water hardness above 100 ppm (parts per million). Water hardness is measured in parts per million or Degrees Clark, as shown in our Quick Guide to Water Hardness.

Calmag Quick Guide to Water Hardness

Degree's ClarkPPMSoft or Hard Water LevelRecommended Treatment
0
1
2
3
0
14
29
43
SoftNo hard water treatment
4
5
6
57
71
86
Moderately SoftNo hard water treatment
7
8
9
10
100
114
129
143
Slightly HardIn regards to the quality of water
some level of treatment is recommended,
choose from:
11
12
13
157
171
186
Moderately Hard
14
15
16
17
18
19
20
200
214
229
243
257
271
286
Hard
21
25
29
300
357
414
Very Hard
30
40
50
429
571
714
Extreme