Sewage Pipeline Blockages

1999 – 2020

The percentage of sewage spills caused by pipeline blockages from 1999 – 2020 is detailed in Figure 4. The percentage of sewage spills caused by pipeline blockages continues to be the leading cause of sewage waste discharges from 1999 – 2020. Since 2009, the increase in the percentage of sewage spills caused by pipeline blockages is primarily due to the significant decrease in the percentage of sewage spills caused by pipeline breaks as shown in Figure 5 (page 11). The significant reduction in pipeline breaks can be attributed to the wastewater collection agencies having to adopt “Sewer System Management Plans” which require the routine inspection, maintenance and rehabilitation of aging sewers. This reduction in pipeline breaks has been maintained at 5% - 8% for the past 10 years.