A case study of rainwater tank water quality testing in Western Sydney, Australia

![CDATA[Stormwater quality and quantity are two important elements in urban water cycle management. In Australia, rainwater tanks are often used to supplement mains water, as part of the BASIX requirement (a New South Wales Government initiative), or as the sole supply of fresh water in many rural households. In addition, rainwater tanks could have other applications such as managing the quantity of stormwater runoff and stormwater quality.A scan of available literature indicated that data for the quality of tank water in Western Sydney in Australia is scarce in the public domain. A study was undertaken to determine the overall water quality of generic rainwater tanks in Western Sydney. The data will be utilised to develop a stormwater pollutant build up and washoff computer-based model for the study catchments. The first part of the research study included monitoring of two rainwater tanks for four weeks. Both the tanks were equipped with continuously logging water quality data probes, a rain gauge and flow meters connected to a data logger, which was downloaded and analysed on a weekly basis. A number of grab samples were collected to determine total phosphorus and heavy metal concentrations. The grab samples were also tested for microbiological activity. All tests were conducted using either Australian Standards or the American Public Health Association methods. The results show identifiable trends between different concentrations of pollutants and rainfalls during the study period. It was found that the water quality of the overflow significantly differed from the closest tap to the rainwater tank, which could indicate the flushing out of heavy metal concentrations and microbiology layer on the water surface after a heavy storm event.]]