The aim of this study was to assess the quality of the drinking water supply in the district of Avellino (Italy), by evaluating physico-chemical parameters and presence of contaminants. A multivariate approach was used to analyse data and to evaluate compliance to norms and standards. Study results indicate that statistical modeling is a powerful descriptive method to identify qualitative temporal trends in water quality and, if repeated in time, allows an evaluation of representativeness of the sampling points.