The goal of this work is to demonstrate the impact of the microbial communities within the drain field in remediating nutrients and detoxifying pharmaceuticals and personal care products (PPCPs) in on-site septic systems. Early data suggests microorganisms play a role in the PPCP transformation in soils associated with septic system leach fields. On-going efforts will elucidate the key microbial communities involved. Non-point nitrogen and PPCP release from antiquated septic systems is not unique to Cape Cod. Seasonal, coastal communities from Maine to South Carolina with a high septic system usage jeopardize sensitive coastal ecosystems vulnerable to eutrophication and PPCPs effects. Other rural communities relying on septic systems that discharge into potential drinking water sources also pose an elevated risk for both ecosystem and human health. Our long-term research goal is to provide sufficient information on nutrient removal and PPCP detoxification within on-site septic systems. This information could motivate and provide a scientific basis for replacing or repairing antiquated septic systems. Upgrading septic systems in areas that cannot adequately support centralized treatment systems could significantly improve the water quality.