A plumber is hydro-jetting a 100 mm building sewer and encounters extremely high back pressure, suggesting a full obstruction. What is the safest next step before proceeding with further high-pressure clearing attempts?

Question: A plumber is hydro-jetting a 100 mm building sewer and encounters extremely high back pressure, suggesting a full obstruction. What is the safest next step before proceeding with further high-pressure clearing attempts?

Answer options:

• Increase the water pressure to dislodge the obstruction.
• Switch to a rotating nozzle to break up the blockage. ✅ Use a sewer camera to assess the nature and location of the obstruction.
• Introduce a chemical drain cleaner into the line.

Correct answer: Use a sewer camera to assess the nature and location of the obstruction.

Explanation: Using a sewer camera allows the plumber to visually inspect the obstruction, identify its type (e.g., roots, collapsed pipe, foreign object), and determine the best approach for removal without causing further damage or creating a dangerous situation. Increasing pressure blindly can rupture weakened pipes, and chemical cleaners are not suitable for severe, unknown obstructions.