Inspection, Testing, and Rehabilitation
What the exam expects
This domain covers how utilities find and fix defects. Know the inspection methods and what each is best at detecting, plus the common rehabilitation techniques and their limits.
Concepts to master
- CCTV inspection: the workhorse for internal defects (cracks, roots, infiltration, offset joints).
- Smoke testing: finds inflow sources and illegal connections; not for structural defects.
- Dye testing: confirms a specific connection or leak.
- Leak and infiltration testing: exfiltration vs. infiltration tests; air testing of new pipe.
- Rehabilitation: cured-in-place pipe (CIPP), slip lining, pipe bursting, spot repairs, grouting, and manhole lining.
- Condition assessment ratings and prioritization.
Traps
Questions often ask which test finds a specific problem. Smoke testing finds inflow, not infiltration from groundwater. CCTV finds internal defects but not external corrosion. CIPP reduces capacity slightly because it reduces inside diameter - a common trap.
Worked example
A neighborhood shows high wet-weather flow spikes. The likely cause is inflow (direct stormwater connections). Smoke testing is the appropriate tool; CCTV would be used afterward to locate structural defects.