How should new sewers be inspected before being placed in service?

• A. With Dye Tests
• B. With Air or Water
• C. With Video Inspection
• D. With Visual Inspection Only

Answer: (B)

Testing new sewers for watertightness before putting them into service is essential because it directly verifies that joints and walls will contain the flow and resist infiltration or exfiltration once in use. The most reliable way to do this is by applying pressure with air or water and checking for any loss of pressure or water level. In an air test, the pipeline is sealed at both ends and pressurized; if the pressure holds for the required time, the line is considered watertight. In a water test, the line is filled with water and monitored for leaks or a drop in water level; any loss indicates a leak that must be repaired. Video inspection or visual inspection alone cannot uncover leaks hidden in joints or within the pipe walls, and dye testing is used for tracing flows or identifying cross-connections rather than proving overall watertightness. That’s why air or water testing is the appropriate method before service.