What plumbing issue is caused by siphonage?

Siphonage occurs when the pressure in a plumbing system drops, causing water in a trap, which is designed to prevent sewer gas from entering a building, to be drawn out. This removal of water from the trap can result in foul odors or the escape of sewer gases into the living space since the trap no longer has the water barrier that serves to block these gases.

In plumbing systems, maintaining a proper water seal within traps is crucial for ensuring that unpleasant and potentially harmful sewer gases do not infiltrate the interior of a building. When siphonage happens, and the water is pulled from the trap, it compromises this seal, allowing those odors to escape into the environment, which can pose health risks and reduce air quality within the space.

The other plumbing issues listed, such as clogged drainage systems, escape of sewer gases, and flooding due to rainwater overflow, do not specifically result from the process of siphonage but rather from other plumbing failures or environmental conditions. For instance, clogged drainage systems typically arise from blockages rather than pressure changes causing water displacement.