Water hardness

Hard water, scale, and spots on glassware

Water described as ‘hard’ is high in naturally occurring dissolved minerals, specifically calcium and magnesium carbonates (chalk).

Hard water can lead to the formation of soap scum (preventing soaps from foaming), and may leave white deposits on hard surfaces or cause scaling problems inside hot water systems and kettles.

• Hard water does not show any adverse health effects.
• South East Queensland water is considered ‘hard’ to ‘moderately hard’.
• Some dishwashers require that you add salt to soften water or need to be programmed to reflect the water hardness.
• Periodic water quality data, including hardness (calculated as CaCO3), can be found here. Conversions to different units (i.e. German degrees, mmol, etc.) can be found using this data and inputting it to a conversion tool.

Drinking water hardness is primarily due to the source of the water (i.e. dam or river) and catchment geology.