Due to the increasing development of nautical tourism, the quality of drinking water on boats has an increasing role. The aim of this paper was to analyze the water quality results on different types of vessels in the Primorje-Gorski Kotar County, in the fifteen-year period from 2002. to 2016. The quality of water was tested in the laboratories of the Health-Ecological Department of the Primary-Gorski Kotar County Public Health Institute. A total of 478 samples were analyzed on basic microbiological and physico-chemical indicators, using standard ISO methods. The results of water quality testing showed that there was a statistically significant difference between years, months, seasons as the type of subject that supplies the water to the analysis. All microbiological indicators, with the exception of total coliform bacteria, have a downward trend. The number of colonies (UBB) and P. aeruginosa has the highest increase in October, as well as indicators of fecal contamination, which appear in elevated concentrations during the summer. Samples delivered by shipyards are better quality than those delivered by shipping agencies. Measurement of the residual chlorine concentration and Legionella test should be routinely investigated.