Which test is used to identify illegal drain connections and cracks, done when groundwater is low and requires notifying authorities?

• A. Dye Test
• B. Smoke testing
• C. Television inspection
• D. Lamping

Answer: (B)

Smoke testing is used to identify illegal drain connections and cracks in a sewer system. It involves blowing non-toxic smoke into the sanitary sewer lines and watching where it escapes. When there are improper connections to storm sewers or cracks in the pipe, the smoke will appear at ground surfaces, through basements, crawl spaces, around manholes, or along utility cuts, revealing the defect. This method works best when groundwater is low because dry or low-water conditions let the smoke travel more easily through small openings and cracks, making leaks and illicit connections easier to spot. Authorities may need to be notified to coordinate for building access, safety, and regulatory compliance, and to ensure the smoke does not trigger alarms. Dye tests use colored dye to trace flows from fixtures and into the sewer, which helps confirm connections but isn’t the recommended method for locating hidden leaks or illicit ties in the underground system. Television inspection (CCTV) looks inside pipes to identify blockages and structural issues but doesn’t reveal where smoke leaks or illegal connections occur. Lamping is an older technique that uses light to spot visible leaks but is less effective for locating concealed defects and illicit connections.