Continued from previous post…

Unlike the supply system, drainage systems do not depend on pressure. Instead, waste matter leaves your house because the drainage pipes all slope downwards. Simple gravity pulls the waste along the pipes. The sewer line continues this downward flow to a sewage treatment facility or a septic tank (although in some low lying areas pumping may be used).

While the system may sound simple, there are numerous essential components to it, including vents, traps, and clean outs, all of which your Whangarei plumber knows well. The vents sticking up from the roof of your house allow air to enter the drainpipes. If there was no air entering from the vents, waste water would not flow out properly and the water in the traps would need to be siphoned away.

Traps are an important part of the drainage system. You can see a trap under every sink or basin. It is the S-shape section of pipe under a drain. Water flows from the basin with enough force to go through the trap and out through the drainpipe, but enough water stays in the trap afterward to form a seal that stops sewer gas and bad smells from coming up into your home.  Toilets are self trapped by the bowl water and don’t need an additional trap in the drain. Some kitchen sinks have grease traps to collect grease that might otherwise cause blockages. Because grease and hair are the common causes of drain blocks, traps sometimes have clean out plugs that give you easier access to remove any blockage.