Which trap is permitted under plumbing regulations?

The correct answer is that full "P" traps are permitted under plumbing regulations because they are specifically designed to provide a water seal that prevents hazardous gases from entering the living space. A full "P" trap is an efficient and effective way to eliminate sewer gases while allowing wastewater to drain properly.

Full "P" traps are commonly used in residential and commercial plumbing systems, ensuring proper drainage and a complete seal. They maintain a water barrier, which is essential for preventing foul odors and maintaining indoor air quality.

Drum traps, crown vented traps, and bell traps are either outdated or may not meet current plumbing codes due to their design, which can lead to issues such as poor drainage or inadequate ventilation. This is why full "P" traps are emphasized in modern plumbing standards and are widely accepted for use in various plumbing applications.