How must garbage disposals be connected in plumbing systems?

Garbage disposals must be connected directly to a sink drain and are required to have a trap in accordance with plumbing codes, including those in Massachusetts. This setup ensures that waste and waste water can flow efficiently from the disposal into the plumbing system while also preventing sewer gases from escaping into the home.

The trap plays a vital role in maintaining this system by creating a liquid seal that blocks odors and gases. Having the disposal connected directly to the sink drain allows for proper drainage and minimizes the risk of clogs or backups. The requirement for a trap is consistent with standard plumbing practices, which aim to maintain sanitary conditions and protect the public health.

Other connection methods, like those involving separate outlets or indirect waste lines, do not conform to the necessary sanitary requirements and could lead to potential health hazards or plumbing issues. Therefore, the correct connection is specifically to the sink drain with the incorporation of a trap, as stated.