Number of sewer overflows in the U.S. 1985-2024, by water body

From 1985 to 2024, at least 8,612 overflows were reported in combined sewer systems in the United States. During this period, the Ohio River was the water body that received the highest number of overflows with almost 500 events. A combined sewer system collects rainwater, and domestic and industrial wastewater into one pipe, to later be transported to a treatment plant. When the capacity of these systems gets exceeded, untreated runoff flows to nearby waterbodies. In the U.S. combined sewers are mostly located in the Northeast.

自1985年至2024年，美国合流式排水系统中至少报告了8,612次溢流事件。在此期间，俄亥俄河成为接收溢流事件数量最多的水体，其溢流事件数量接近500起。合流式排水系统汇集雨水、生活及工业废水于同一管道，随后输送至污水处理厂。当系统容量超出其承载能力时，未经处理的径流将流入邻近的水体。在美国，合流式排水系统主要分布于东北部地区。