Due to sediment contamination, the EPA designated the Lower Willamette River between the Fremont Bridge and Sauvie Island as the Portland Harbor Superfund site in December 2000. The City of Portland owns over 20 stormwater or combined sewer outfall pipes that drain into Portland Harbor. The City is a potentially responsible party because of the potential of the City's stormwater system to carry contamination from upland areas to the river. The EPA ordered this investigation to identify the cause, extent and nature of Portland Harbor contamination and to evaluate health risks to humans, fish and wildlife.
The Superfund charge is not a new charge. In July 2007, the City added a Portland Harbor Superfund Program line item to the City water and sewer bill to show ratepayers exactly what portion of their sewer bills pay for the Portland Harbor investigation. City of Portland sewer rates have paid the City's share of this investigation since 2001.
The charge is based on both impervious area (I/A) and sewer volume (measured in one hundred cubic feet, or CCF). The current rate for the Superfund charge is $0.09 per each CCF of billed sewer volume and $0.24 per each thousand square feet of I/A (Impervious Area) per month. The $0.09 is based on either the actual measured water volume or on the winter average, whichever is less.
More information about the Portland Harbor cleanup is available from the The Bureau of Environmental Services.