What is the purpose of pouring another cup of antifreeze down the drains during winterization?

Pouring antifreeze down the drains during winterization primarily serves the purpose of preventing the p-traps from freezing and subsequently cracking. P-traps are plumbing components that hold a small amount of water to create a seal, which prevents sewer gases from entering the building.

By adding antifreeze to the drains, it ensures that no water remains in the p-traps during freezing temperatures, thereby inhibiting any potential damage that can occur if ice forms. This preparation is essential to protect plumbing systems in regions where winter temperatures could drop significantly.

While the intention may seem similar to other options, they do not directly address the critical function of safeguarding against freezing temperatures in the plumbing system, which is the primary reason for this winterization step.