The utilisation of rainwater tanks and bore wells are very common in many parts of rural Australia and Papua New Guinea. In Australia, on-site collection and storage of potable water for domestic use is carried out by approximately 30.4 percent of the rural population while 90% of the population in Papua New Guinea access water from on-site collection and storage of potable water. Few studies have monitored the quality of such water supplies on a seasonal and event associated basis. The aim of this study was to evaluate the microbiological and physio-chemical properties of the on-site domestic water supply systems and various factors that may influence characteristics of the water. It aimed to evaluate the relationship of microbiological and physio-chemical characteristics in the water supply systems. 14 rainwater tanks, 4 bore well and 10 reticulated water supply sites in Hawkesbury District, NSW Australia were investigated. Characteristics of the sites physical situation and natural environmental condition were considered to be similar to on-site water supply situations in Papua New Guinea. The results and techniques of the study will be used as a model in Papua New Guinea in the assessment of water quality issues. As the study showed that the quality of water in rainwater tanks was below WHO guideline recommendations on numerous instances, it was proposed that water treatment and maintaining the cleanliness of roof catchments, gutters and tanks should be addressed for domestic use systems. A protocol for sampling, assessment and data interpretation of faecal indicator bacteria populations in domestic catchment supply systems was developed and demonstrated / Master of Science (Hons)