Amongst the curbside recycling programs, single stream recycling (SSR) has grown rapidly during the past decade due to its capabilities to increase participation rate while reducing the collecting cost and avoiding a cumbersome sorting process at the individual level. However, SSR systems operate at the expense of facing significant technical and economic barriers in terms of higher contamination in collected materials. Therefore, leading to higher volumes of materials requiring pre-sorting at regional material recovery facilities (MRFs), and reliance on export markets. An increase in contamination in the inbound stream translates to an increase in sorting and separation, a reduction in quality of recycled material and also an increase in the total processing cost of recyclable materials. The purpose of this study is to identify the contamination rates in the SSR inbound stream and to determine the extent to which SSR is responsible for the contamination of incoming materials. This study used regression analysis to identify major demographic contributors to fiber contamination rate and provide suggestions that could help the minimization of contamination considering various region-specific factors. From the results obtained, low median age is associated in increasing contamination level. Low median age and low median household income are associated with increasing glass contamination while low median household income is associated with increasing plastic contamination rate.