The collection and conveyance of sanitary wastewater is a principal tenet of sanitary engineering that has helped move developed countries into the modern urban age. The focus of collection system agencies has historically been to convey wastewater to treatment facilities. The operational practices of these agencies have generally been geared toward infrastructure maintenance and repair. System design anticipates some overflows due to inflow and infiltration during wet weather periods, materials and construction practices, the geography of the area, the size and duration of wet weather events and many other variables – often site specific. Over the last 10 years, NPDES permits for collection systems have been considered. This national effort has stalled for a number of reasons, but California recently moved forward with a state-wide permit program, issuing new state Waste Discharge Requirements (WDRs) to over 2000 collection system agencies, many of which are satellite collection systems that have never before been subject to a permit. Over the last 5 years, there appears to be an increasing trend of Non Governmental Organizations (NGOs) bringing third party Clean Water Act (CWA) lawsuits against collection system agencies for sanitary sewer overflows (SSOs). This paper will review these emerging regulatory and legal “challenges” to collection system owners with a focus on the exposure of collection system agencies. While many of these new external pressures on collection system agencies appear to be focused in California, it is expected that given the “success” of these lawsuits, it is inevitable they will spread nationally.