When it comes to plumbing, it may seem like your technician is speaking a language all on their own. While the Ontario drain and sewer line service experts from All Pro Plumbing, Heating, Air & Electrical will always do everything they can to explain things in the simplest terms possible, it’s important for any homeowner to know some basic terms in order to better understand their plumbing. Drains and sewers specifically have a variety of words and phrases that are all important to know, so here’s a list of some of the most important ones you should know.

Drain Terminology

House Sewer

The house sewer is a drain line which connects the drainage system in your home to either the public sewer or your septic tank. If you think of your drainage system like a tree with many branches, your sewer line is like the trunk of that tree. All of the various drains in your home end up in your sewer line, and thus it’s arguably the single most important part of your drain system. This is also sometimes referred to as your “sewer main.”


Whereas your sewer is the trunk of the tree that is your drainage system, the various drains are like your branches. Each drain starts at a plumbing fixture, including a sink, toilet, shower, tub, or even an appliance like a dishwasher or washing machine. There are also drains which aren’t actually connected to any sort of a plumbing fixture, including things like storm drains, irrigation drains, perimeter drains, and much more. The average home can have around two dozen drains or more.


A trap is a part of each drain line which is tasked with preventing air or gas in a drain line from passing back up the line and coming back out the drain itself. Ever wondered why your home doesn’t reek of the brutal smell of your drain or sewer lines? You have your traps to thank for that. Take a look under the sink in one of your bathrooms, and you’ll likely notice that there’s a 180-degree U-shaped bend where your pipe actually flows back upwards for a few inches before draining away. This is the “trap” and it’s designed to stay full of water in order to block the passage of air and gasses.

Explore Our Drain Services

Vent Piping

Vent piping is a feature in your drain system that’s designed to prevent back pressure from clogging or contaminating your drainage system. Have you ever tried to pour water or milk out of one of those plastic gallon containers too quickly and noticed how the water always seems to come out in pulses? This is because the water that leaves the gallon forms a vacuum, and that vacuum needs to be filled with air before more water can flow out. This same principle can happen in your drains, and your vent pipe ensures this doesn’t happen. The vent usually sticks out of your rooftop, and usually several different drains in the same vicinity are all connected to the same vent pipe.


This term refers to pipes which carry discharge from various drains in your home. There are two different types of stacks. “Soil” stacks refer to any drain line that carries discharge from your toilets, whereas a “waste” stack refers to any length of piping which carries discharge from all other drains besides your toilets. The name “stack” refers to the vertical runs in each of these pipes.

Sub-House Drain

A sub-house drain is any drain which dips below the level of your home or your main sewer line, which means it can’t use the natural power of gravity to carry discharge away. While they aren’t extremely common in most homes, businesses with underground parking structures or subterranean features often have sub-house drains.

Do you need a drain repaired or a new drain installed? Got a problem with your sewer line? Call the experts at All Pro Plumbing, Heating, Air & Electrical at (909) 500-8193 today.