This data set establishes the missing link between drinking-water quality monitoring data at the water production facility level in the Danish national geodatabase Jupiter and supply areas. Water Supply Areas (WSAs) were collected at municipality level, digitised and linked to the waterworks they are supplied by. Infrastructural changes between 1978 and 2019 were taken into account by allowing WSA polygons to change over time. The number of active WSAs decreased from 3172 in 1978 to 2602 in 2019. The data set consists of longitudinal WSA polygons and a table linking WSAs to the water production facility identification in the Jupiter database, allowing the estimation of cur-rent and historical drinking-water quality across Denmark. In combination with the Danish Address Register and the Civil Registration System, this data set allows exposure assessments of drink-ing-water quality at high spatiotemporal resolution for the entire Danish population. Therefore, this data set is an essential part of studying health effects of drinking-water quality in epidemiological research in Denmark.