The first type of cleaning pig to be sent through a main is called

• A. Bare pigs
• B. White pigs
• C. Red pigs
• D. Gags pigs

Answer: (A)

The first cleaning pass uses a bare pig. It’s a smooth, non-abrasive plug, designed to seal and travel through the main with minimal resistance. This initial pass gently pushes out loose debris and clears the line enough to assess how the system behaves before applying more aggressive cleaning methods. By starting with a bare pig, you reduce the risk of damage to the pipe while establishing a baseline for flow and cleaning effectiveness. After this baseline, you bring in more thorough cleaning pigs (with bristles or other features) to tackle tougher deposits.