After a few years in operation there should be an evaluation of operating results out of the self-monitoring of the Reinhaltungsverband Region Neusiedlersee-Westufer and the water authorities. This thesis should be a basis for the preparation of a study on a cause-based allocation of funding and operating costs The analysis consists of historical data, notes of the Reinhaltungsverband Region Neusiedlersee-Westufer and the water authorities and a study of Dipl. Ing. Dr. Novak of 1993 were used. The study contains 3 points infiltration/inflow, viniculture and tourism. There was an evaluation of infiltration/inflow, including the ground water conditions, lake water levels and implemented sewer renovation. Furthermore, the thesis should be an assessment of the development of pollutant load contributions of tourism (festival, day-trippers) and of viniculture (development of wine yards, structures). A direct correlation between groundwater level and infiltration water wasnt detected in any of the communities. In relation to the lakewaterlevel theres a partial correlation in Schützen, Oggau and Mörbisch in 2001. In Rust and Oslip for the years 2001 and 2002, infiltration/inflow corresponds with the the lake water levels.The pollution loads are liable to annual fluctuations, the main peaks are in July (COD, BOD5) and October (TOC, BOD5 and COD). These peaks are caused by both, viniculture and tourism. A detailed separation of pollution loads into tourism and viniculture cannot be made. Overall gesN and gesP have a periodic increase and decrease. The peaks usually occur in October. This could be due to viniculture, as both the inflow amount and the pollution load increase dramatically.