The general problem of lake eutrophication is presented. The
trophic situation of Sardinia man made lakes is also shown.
Among 25 of 38 reservoirs located in Sardinia 4 are oligotrophic, 4 mesotrophic and 17 eutrophic. It is pointed out the need of monitoring the trophic status of all reservoirs and the need of eutrophication control because of drinking utilization of lake waters