Most water supply programmes in Cambodia have focused on providing access to bacteriologically safe water, an approach which has led to an increasing reliance on ground water, especially in rural areas. However, there have been very few data collected on the chemical quality of the nation's drinking water sources, and few water supply programmes have the capacity to assess chemical quality. The study was designed to address this data gap by conducting a low-cost, rapid assessment of drinking water sources nationwide to determine whether there were any chemicals of concern in Cambodian water supply sources. Results of the assessment confirm that there are several parameters of health and aesthetic concern; dissolved arsenic is the most significant. Elevated arsenic levels (some exceeding 500 μg l-1) were detected in aquifers of moderate depth in several highly populated areas, confirming that further investigation of the occurrence of arsenic contamination in Cambodia is warranted. Other chemicals of health concern include nitrate, nitrite, fluoride and manganese. Additionally, many ground water sources are negatively impacted by parameters of aesthetic concern, such as iron, manganese, hardness and total dissolved solids. Elevated levels of these parameters have caused consumers to reject newly installed water supplies, often in favour of surface water sources that are bacteriologically unsafe.