ABSTRACT: The special environmental protection area,,, covering 266 km area on Umd and 23 km. area- on sea in andaround Fethiye, includes Fethiye., Göcek, İnlice and Kayaköy plains: Surface and graundwaters in the area havebeen investigated and- kydrochemical characteristics of waters were determined using pH, TDK, EC, Na, Kg Ca»Mg, HCOs., CO?, SO4, Cl, NOs ve NH4 parameters in a project supported by the Special Environmental ProtectionAgency of Turkey. These parameters and the quality classes of waters» which were calculated using both irrigation water limits and spring water limits, were evaluated in GIS environment through TNT-MIPS software.Groundwaters in the area are Mg/Ca/Mixed-HCOs type that reflects the chemical interactions betweengroundwaters and litological units., According io spring` water TDS, Cl, N-NO* and SO4 limits, groundwaters arehigh quality or little contaminated, according to irrigation water SAR, %Na, Ci and SO4 limits groundwaters arehigh or good quality` and according to irrigation water EC and Nos limits groundwaters are good or mediumquality,. Two water quality maps were prepared for the area using ail spring water and all irrigation water parameters, separately, assigning` the*,same weight. The quality map of spring water classification suggests that thearea includes quality indexes of 4, 5, and 6 in the range of 4 to 16. The quality map of irrigation water classification suggests that the area includes quality indexes of 7, 8, 9, 1ft and 1.2 in the range of 6 to 30. As a result ofthese applications, it has been concluded that groundwaters in the area are of good quality in terms of the measured parameters.. Koca Göl lake water in on the other hand, is contaminated- by Cl, SO* ve Na ions. Naturalsources of contamination are the sea water that mixes with the lake water and the mineral waters rich in SO* present in vicinity of the lake. Although no pollution has been detected in the groundwaters, there are potential pointcontamination sources in the area.. These are waste disposal sites of the munidpitalities, Eti Holding chromiumprocessing plant, a fertilizer warehouse., and chromium and manganeze mineralizations in the region