Linear models in the arithmetic domain were developed by minimizing sum of squared errors in the logarithmic domain between Escherechia coli (EC) and fecal coliforms (FC), and enterococci (NC) and FC for various sources and in-stream locations in the lower Passaic River at Paterson, New Jersey. This modeling procedure has the advantage of being linear in the arithmetic domain making interpretation of the model easier, while also reducing the impact of influential observations on the regression. All bacteria sources, i.e. combined sewer overflows, stormwater, and tributaries, had lower EC/FC ratios than that at the upstream boundary Totowa. The in-stream sites immediately downstream of Great Falls and upstream of Dundee Dam had the highest EC/FC ratios, despite its upstream site and intermediate sources, having lower EC/FC ratios. The results indicate combined sewer overflows (CSO) contribute significantly between Northwest and Lincoln and Lincoln and Morlot sites.