Drains work by using simple gravity. When you push down the sink plunger, the drain sucks water through the opening into the appliance drain line. As the water falls straight down the vertical appliance line, it gathers speed and velocity. That speed allows it to move past the p-trap and into your home’s drainpipes.

How do bathroom sink drains work?

The sink drain has a flange that is sealed to the sink hole with plumber’s putty. This flange is screwed into the drain body, which is tightened to the underside of the sink bowl with a locknut. The tailpiece, which may be fitted to a pop-up stopper, attaches to a drain trap by means of slip-joint couplings.

How does a kitchen drainage system work?

Drainage systems do not depend on pressure, as supply systems do. Instead, waste matter leaves your house because the drainage pipes all pitch, or angle, downward towards the sewer. Gravity pulls the waste along. The sewer line continues this downward flow to a sewage treatment facility or a septic tank.