Why do public water supplies need to be clear and free of unpleasant tastes and odours?

Public water supplies are required to be clear and free of unpleasant tastes and odours primarily for aesthetic reasons rather than direct health concerns. These physical characteristics—colour, taste, and odour—are managed to ensure the water is acceptable for domestic use, such as drinking and cooking.12

While these factors are distinct from health-related primary standards, they are addressed through secondary standards that provide guidelines for water quality. For instance, colour may result from decaying organic matter or algae, while tastes and odours can be caused by dissolved gases like hydrogen sulfide or naturally occurring organic substances. Additionally, certain dissolved metals like iron, manganese, copper, and zinc can impart bitter tastes and cause staining on plumbing fixtures or laundry.31

To maintain these aesthetic standards, water treatment facilities employ processes such as aeration to remove dissolved gases and carbon adsorption to eliminate organic impurities.45