Massachusetts Plumbers Journeyman Practice Exam 2026 – All-in-One Guide to Master Your Licensing Test!

The correct answer is liquid waste. Liquid waste refers to any discharge coming from fixtures, appliances, or areas that does not include human or animal waste. This encompasses a wide range of non-hazardous discharges such as water from sinks, showers, or appliances that handle wash water, making it a significant category in plumbing definitions and practices.

Other options do not fit this definition. Air represents a gas, while developed length pertains to the physical layout of piping in a system. Trap seal refers to the body of water maintained in a trap to prevent sewer gases from entering the building, which is unrelated to the discharge characteristics defined in the question. Thus, focusing on the nature of liquid waste provides a clear understanding of what qualifies as discharge without harmful waste.