The answer to 'which is better P-trap or' is that both P-traps and S-traps are effective plumbing options, but the P-trap is generally considered the better choice for most residential and commercial applications. P-traps are more efficient at preventing sewer gases from entering the home and are less prone to clogging than S-traps.
P-traps feature a U-shaped bend in the pipe that holds a small amount of water, creating a seal that blocks odors and pests from entering the home. S-traps, on the other hand, have a vertical section that can allow water to siphon out, breaking the seal and allowing sewer gases to escape. P-traps are also easier to access and clean if a clog occurs, making them a more convenient and reliable option for most homeowners.