What is the minimum trap seal required in plumbing systems?

The minimum trap seal required in plumbing systems is two to four inches. This measurement is crucial for maintaining effective drainage and preventing sewer gases from entering the living spaces. A trap is a U-shaped bend in the plumbing that holds a certain amount of water, effectively creating a seal against the backflow of gases and odors from the sewage system.

Having a minimum trap seal of this size ensures that the plumbing system operates efficiently, preventing issues such as clogging or the loss of the trap seal due to evaporation. If the seal is too shallow, it may not provide an adequate barrier, leading to potential health risks and unpleasant odors infiltrating the building. Thus, two to four inches is established as a standard to balance effective drainage while ensuring that there is a sufficient water barrier against harmful gases.