What is a common consequence of improperly vented plumbing systems?

Improperly vented plumbing systems can lead to a buildup of negative pressure in the pipes, which disrupts the normal flow of air and water. This can result in the presence of foul odors emanating from drains. Proper venting allows sewer gases to escape and helps maintain the right pressure within the plumbing system. When a venting system is inadequate, trapped gases can push up through the drain, resulting in unpleasant smells in living spaces.

In contrast, although increased water pressure, frequent clogs, and water leaks may seem like potential issues related to plumbing, they are typically associated with different causes. Increased water pressure could arise from another source entirely, and frequent clogs usually result from debris buildup or pipe narrowing rather than venting issues. Water leaks often result from faulty fittings or broken pipes. Thus, foul odors from drains most directly link to the consequences of improper venting in plumbing systems.