The District is currently responsible for approximately 4,720 manholes and uses three (3) methods of inspection to check each manhole on an annual basis. The primary method of inspection is the “routine manhole inspection” task. One employee with a pickup truck drives to their designated area and systematically inspects each manhole. In addition to identifying problems and/or defects with the manhole, employees look for signs of trouble in the pipeline system such as grease accumulation, high water in the manhole or dark water flows indicating partial blockages. Any problems are noted on a manhole inspection form. This information is loaded into the District’s Maintenance Management Information System (MMIS) and used to schedule future work. Inspection personnel will notify the pipeline cleaning crew if a flow problem needs immediate attention.
Manholes are also inspected during routine maintenance tasks that require the removal of manhole covers. Crews check manholes and record problems or defects when they are performing such tasks as pipeline cleaning or CCTV pipeline inspection.