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Sewers and Their Maintenance: Keeping the Underground Lifelines Flowing


How We Keep Sewers Working

maintenanceOperations and maintenance activities are ’round-the-clock, 365-days-a-year. Major activities focus on operations, preventive and corrective maintenance, and emergency response. Many maintenance activities focus on tree roots and fats, oil and grease (FOG) that clog the sewers. The number of sewer spills (overflows) in the City has significantly decreased over the past five years as a result of these efforts. These include:

  • sewer and maintenance hole inspection – over 2,600 miles of sewers are inspected annually; over 600 miles are inspected by closed circuit television each year.
  • sewer cleaning – more than 2,600 miles are cleaned annually.
  • hot spot sewer cleaning – at least 1,500 miles are cleaned annually.
  • root control – chemicals are applied to a minimum of 150 miles annually.

FOG-Related Sanitary Sewer Overflows - by Fiscal Year

FOG SSO 09 10 rs

Root-Caused Sanitary Sewer Overflows - by Fiscal Year

ROOT SSO 09 10 rs