This page contains the list of italian regions. By clicking on the selected region will result on region main page with its related provinces listed. Select the province of your choice to show towns list. Click on the town name to access the water quality information (as given by their respective water supply providers).
Note about the provided links: unfortunately, as you'll see, most of the linked websites (italian potable water providers web pages) are in italian language only. To get tap water quality information, search for words like: "etichetta dell'acqua" or "qualità dell'acqua" or "analisi qualità".