Longitudinal sampling from rainwater tanks and mains water throughout Australia was utilised to analyse the metal and elements in water supplies. Investigations aimed to determine the distributions of elements in stored rainwater in urban or rural locations and for roof types. The elemental composition mains water samples were also investigated. A majority of analysed samples were compliant with Australian Drinking Water Guideline values for metal and elements, although 12% of samples exceeded guideline values for one or more element. However, repeated non-compliance with guidelines was rare.
Mains water samples were found to contain significantly higher concentrations of sodium, strontium, barium, magnesium, and molybdenum, and significantly lower concentrations of manganese and zinc compared with tank water samples. Urban tank water samples contained significantly higher concentrations of strontium, barium, chromium, and molybdenum than rural tank water samples and significantly lower concentrations of iron, cadmium, manganese and copper compared with rural tank water samples. The concentrations of certain elements in samples from rainwater tanks with different roof catchment materials were also found to vary significantly.