Auckland’s groundwater sources fall in the ‘soft’ or ‘moderately hard’ category and are well within the recommended range stated in the New Zealand Drinking Water Standards
. This range is based on guidance from the World Health Organisation
While naturally occurring, these minerals can build up on domestic appliances and smooth surfaces in the form of ‘scale’. The scale may contain one or a combination of several compounds like calcium carbonate or silica. It may appear on shower doors and tapware, or in kettles and hot water systems.