What is an S-trap commonly used for in plumbing?

An S-trap is primarily designed to prevent odors from entering the living space, which is crucial for maintaining indoor air quality. The trap creates a water seal that blocks sewer gases from rising through the plumbing and into the home. When water fills the U-shaped bend of the S-trap, it effectively seals off the pipe from the air outside, ensuring that any unpleasant odors remain contained within the wastewater system.

The other options relate to different plumbing functions. For example, connecting pipes at right angles generally involves fittings like elbows, which serve a different purpose than an S-trap. While flat drainage systems do rely on proper sloping and effective trap designs, that is not the main function of S-traps. Additionally, while ease of cleaning might be a consideration for certain plumbing fixtures, the primary role of an S-trap is its ability to maintain that crucial water seal to prevent foul smells from infiltrating living spaces.