What is Calcium & Magnesium (Hardness)?
The two most common elements that contribute to water hardness are calcium and magnesium. When these precipitate from water they leave a white powdery precipitate that is often called lime scale.
The New Zealand drinking water standards give a guideline value of <200mg/L. However it is important to note that the drinking water standards are concerned with drinking water rather than plumbing. Issues around the home are noted at much lower levels.
The world health organisation recognises this and give the following descriptions:
|<60mg.L||Soft Water||This means little or no lime scale found|
|60-120mg/L||Moderately Hard||Lime scale noted particularly where water is heated|
|120-180mg/L||Hard||Scale will form where hot or cold water comes into contact with fixtures|
|>180mh/L||Very Hard||Severe scaling expected|