You are called to a commercial building where a floor drain in a janitor's closet is completely backed up. The building has a history of misflushed items. What is the safest and most effective initial method for clearing this type of blockage?

Question: You are called to a commercial building where a floor drain in a janitor's closet is completely backed up. The building has a history of misflushed items. What is the safest and most effective initial method for clearing this type of blockage?

Answer options:

• Pouring a strong acid-based chemical drain cleaner ✅ Using a high-pressure hydro-jetter
• Attempting to clear with a standard plunger
• Dismantling the drain P-trap for manual removal

Correct answer: Using a high-pressure hydro-jetter

Explanation: For commercial floor drains with potential misflushed items, a high-pressure hydro-jetter is generally the most effective and safest initial approach to clear stubborn blockages while preserving the piping. Plungers are often insufficient for commercial blockages, chemical cleaners can be hazardous and damaging, and dismantling the P-trap might not be feasible if the blockage is further down the line.