Drinking water probably contributes less than 5 per cent of the total human intake of aluminium. Although some studies have suggested a tentative link between aluminium and Alzheimer’s disease and dementia, the evidence as a whole does not support a causal association. Accordingly, there is no health-based guideline for aluminium in water.

The drinking water guideline level for aluminium (0.2 mg/L) was set for aesthetic purposes only (NHMRC and ARMCANZ 1996). Elevated levels can result in customer complaints about milky-coloured water.

Compliance with the aesthetic guideline for aluminium by Sydney and Hunter Water Corporations (SWC, HWC) has been good since 1993. In 1994, SWC phased out the use of aluminium-based coagulants in water treatment, replacing these with an iron coagulant.

Lead can be present in drinking water owing to its presence in natural sources and/or as a result of household plumbing. The greatest potential for lead contamination of drinking water arises from the household reticulation system. Lead can be present in lead piping in older houses. More commonly, lead can be leached from the solder used for pipework, and from certain fittings such as taps.

Moderately elevated blood lead levels, if sustained over the lifetime of a pre-school-aged child, have been linked to impaired neurological development, growth and hearing acuity.

Levels of lead in major Australian reticulated supplies range up to 0.01 mg/L, with typical concentrations of around 0.005 mg/L (NHMRC and ARMCANZ 1996).

Monitoring conducted since 1993 indicates that the SWC and HWC complied at all times with the 1987 guideline level for lead in water of 0.05 mg/L (unpublished data). Compliance was also good in rural water supplies, with between 99.7 and 100 per cent of samples tested meeting the guideline over this period (unpublished data).