How does plumbing work, and when do I need sewer service?

dreamstime_xxl_15298535How does my plumbing system work?


Hey Folks!

So many times we get calls from customers who just don’t get how their home’s plumbing & waste system works. Today, I am here to help!

First, plumbing is made up of two main systems: water and waste

First the difference between a water system and waste system are:

1. Water systems transport clean water through your house. This is would be water to sinks, bath tubs, toilets, washing machines, water heaters, and outdoor spigots and sprinklers.

2. Waste systems transport dirty water away from your house. These would be where drains are found- all connected to the above water systems listed above.

If you are like me, you remember anatomy class. (You betcha, I remember! *wink*) And you remember un-oxygenated blood flows to the heart (blue), and oxygenated blood flows away from it (red).

This is kinda like how your plumbing system works. Clean water flows in (blue), and dirty water flows out (red).

If we pretend a washing machine is a heart, we see clean water fill up the basin and wash the clothes, and when it empties, the water runs into the drain. Blue in, red out.

The difference for Garvin’s is whether we send someone with skills and training in plumbing (clean water blue) or in drain cleaning (dirty water red) and sewer service. There is different training for each specialty, so, we separate the departments. This helps customers get the very best skill set to take care of their unique problem, don’t cha know.

Simple enough so far? Here’s the next anatomy lesson:

The sewer line is like a spine. It is typically 4” in diameter and runs from your house out to a city main or septic tank. The sewer line has a vent pipe that runs all the up to your roof. (Which is why sometimes you hear people say they will go from the roof vent).

Off of the sewer line, sprout secondary lines within the house, which are usually 2” lines. These would be like arms and legs. These lines run off the sewer line to all the different drains in your house, so like, a bathtub and sink, etc. They may be connected to each other vertically, like a bathroom on the first and second floors, OR they can be connected horizontally, like a bathtub and toilet in the same bathroom.

Sometimes an arm AND a leg have a problem, and they both need attention. An example would be a plugged kitchen sink and a plugged bathtub.

Other times, when something is wrong with two areas, the problem is most likely, in this sewer analogy, the spine. We can determine this by seeing if a drain in one area affected, or if toilets being flushed make the problem worse. If toilets worsen the problem, or if they are the point of the backup, it is the sewer that is blocked and will need sewer cleaning. (We can check that with our sewer scope.) Holy buckets! Then you can have a mess!

Sewer lines back up at the lowest part of the house- this could be a basement floor drain, basement or lowest floor bathroom (tub or toilet). When a toilet starts gurgling on a lower level,  that could be a sign you are going to have a sewer backup.

Call us and we can walk you through determining what your plumbing problem might be! In the Greater Denver and Boulder areas, call 303-571-5114.


Got any other questions for me?

Comment here or on Facebook, e-mail AskPlumbingGirl @

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