Water pollution is a significant problem worldwide, particularly in Brazil where the majority of urban populations rely on drinking water from surface water reservoirs. The accumulation of plastic debris, such as polycarbonate blends, in reservoirs and other waterways is a public health issue because of health and environmental concerns associated with their chemical degradation. A compound commonly found in plastics, 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A; BPA), has become a serious environmental problem due to its release in water and its estrogen-like properties. This paper focuses on understanding the degradation process of two types of plastics containing BPA, polypropylene (PP) and poly(lactic acid) (PLA), in surface waters. The strength of the chemical binding of BPA to PP and PLA was examined using thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. Release of BPA from both types of plastics was determined in surface water samples collected from the Billings Reservoir, the largest source of drinking water of Sao Paulo residents. The results show that BPA bound to PP-based plastics is released more rapidly into surface waters than that bound to PLA-based plastics.