The answer to 'best P-trap' is that the best P-trap for most residential plumbing systems is a standard 1.5-inch or 2-inch PVC or ABS P-trap. P-traps are a critical component of any sink, shower, or floor drain, creating a water seal that prevents sewer gases from entering the home.
P-traps work by maintaining a small amount of water in the curved section, which blocks odors and pests from coming up through the drain. They are easy to install, inexpensive, and durable. When properly installed and maintained, a quality P-trap will provide reliable performance for many years.