Freshwater is threatened by climate change and pollution, straining water resources, especially in regions already facing water stress. One of the most recurrent impairments of surface water is fecal contamination, as it could contain pathogens that can cause illness or death in human populations. In Arizona, water scarcity and fecal contamination are primary concerns. While existing studies examine the drivers of fecal contamination, these have primarily been completed in temperate and humid regions, with few studies focused on arid and semiarid regions. We cleaned and synthesized observations of Escherichia coli (E. coli) concentrations in surface water from the Arizona Water Quality Database and completed two different statistical analyses to evaluate relationships to point and non-point sources, climatic and terrain conditions, land cover, and stream networks using 4,558 E. coli concentration records from 610 sites in the period 2010 to 2019. The statistical analysis revealed significant differences between median E. coli concentration distributions sampled from different stream types (17.5 CFU/100 mL in artificial paths, 25.9 CFU/100 mL in perennial streams, and 42.6 CFU/100 mL in intermittent + ephemeral streams), and across antecedent rainfall conditions. At the watershed level, five of the 128 studied characteristics had the most significant relationship with E. coli concentration values and were primarily related to livestock production, land use, and antecedent rainfall conditions. The outcomes of this work can help identify sources and patterns in E. coli occurrence in arid and semi-arid areas, particularly when paired with source tracking or modeling approaches, for environmental management and human health management strategies.