What is hard and soft water
When water falls as rain, it is "soft" and free of minerals. It picks up minerals as it passes through rock, sand and soil, so most water drawn from an aquifer will be ‘hard’. Hard water is high in mineral salts, especially calcium and magnesium. Hard water, generally, is not harmful to our health and may indeed be beneficial.
Hard water isn't bad water, any more than soft water is 'good' water. For example, many tea and coffee drinkers do not like their drink made with soft water, preferring a degree of hardness. Generally people used to soft water will find hard water difficult and vice versa.
The sum of all calcium and magnesium compounds in water results in the total hardness, measured in milligrams calcium carbonate per litre (CaCO3 mg/L).
Water hardness is described as an "aesthetic determinand" in the Drinking-water Standards for New Zealand 2005 (Revised 2008).
This means a property that can adversely affect taste, colour or general appearance of water. Guideline values (GV) are applied to aesthetics – these are levels that if exceeded, may make the water unattractive to consumers. The GV for total hardness is 200mg/L CaCO3.
Certain house hold appliance installation instructions ask if your water is Hard or Soft or what is the pH level of your water.