Water quality in the upper San Antonio River (SAR) Basin was examined in the city of San Antonio, Texas as a function of land use. Sites were representative of different point and non-point pollution sources on the land adjacent to the river. Site 1, located approximately 5 m from the headwater of the SAR, was the control site. Site 2 was in the vicinity of a discharge pipe from the San Antonio Zoological Gardens. Site 3 was immediately downstream from a municipal discharge pipe (San Antonio Water System). Site 4 was situated between a golf course on one side of the SAR and a residential zone on the other. Site 5 was situated in a light industrial zone. Surface grab sampling were performed on a monthly basis between November 2004 and April 2005 excluding January. Water quality parameters measured included temperature, pH, dissolved oxygen (DO), conductivity, oxidation-reduction potential, turbidity, alkalinity, hardness, total phosphorous, and total nitrate-nitrogen content. Results were analyzed by one-way ANOVA and Tukey's multiple comparison tests in order to determine potential significant differences amongst the sites for each parameter. Findings were also compared to state (Texas Environmental Quality Commission) and/or federal (U.S. Environmental Protection Agency) limits in order to establish the parameters out of compliance. Preliminary results suggest that there is variability in water quality data from each site representative of a particular land use and that several parameters are in excess of either state or federal maximum permissible levels or federal non-enforceable guidelines.