This study aimed to investigate the point and diffuse pollution sources of high total phosphorus (TP) pollution detected in the dry and wet seasons of the industrialized and urbanized Saz-Cayirova Basin through field observation and multivariate statistical techniques. In this context, nineteen water quality parameters were analyzed in surface water samples collected monthly between June 2020 and July 2021 from nineteen different sites along the Saz-Cayirova stream. Firstly, two reference sites representing a better surface water status were determined and assessed the water quality on the stream tributaries affecting the wastewater treatment plant in the two Organized Industrial Zones (OIZ). Secondly, hierarchical cluster analysis (HCA) and principal component analysis (PCA) were performed to evaluate the complex water quality dataset and reveal the latent sources of TP pollution. The results showed that the tributaries in the pressure of OIZ discharges were highly enriched in COD, TOC, NO3-N, NH3-N, and TP concentrations compared to the reference level. Compared with reference sites, the concentrations of the four heavy metals examined were at a plausible level. Besides, the pollution sources of TP were industrial processes wastewater such as dyeing, washing, phosphating, domestic wastewater from OIZ, urban diffuse waters with organic character, and continuous discharges of undefined sources. The seasonal variation of TP values is observed relatively low, indicating that the stream network is greatly affected by point source pollution. Our observation and analysis imply that the treatment technologies adopted by the OIZ wastewaters plant is sufficient to treat heavy metals. However, measures need to be formulated to remove TP and organic pollution from the secondary production process.