A trap in plumbing is one that is generally located within or below a plumbing device. The most common type is referred to as a P-trap. This is created by the addition of a 90 degree fitting found on the outlet side of a U-bend, which creates a P-like shape. It also is referred to as a sink trap because it is often installed under house sinks.
Because of its shape, the trap itself is helpful in retaining small amounts of water after the fixture is used. This water creates a seal that helps to prevent sewer gas from passing through the pipes. Ultimately, all fixtures including bathtubs, toilets and sinks must have either an internal or external trap for this reason. These traps often collect sand, other debris or hair, which allows them to be disassembled for cleaning.
A professional plumber can inspect a home’s current plumbing system to guarantee it is running properly and efficiently.