Understanding Underground Plumbing Systems: A Detailed Review

The first plumbing drawing we are going to review is the underground plumbing beneath the garage. We have a keynote legend, and you will be referring to this frequently. The two dominant types of underground plumbing systems are sanitary and stormwater.

The two pipes are differentiated by different line weights on the drawing. As we zoom in, you will notice that one line is darker and one is thinner. The thinner line represents the sanitary system, while the darker line represents the stormwater system.

Here you can see it says there is a six-inch storm line from above. This is essentially a drain pipe that then feeds into the system. This is a cleanout, as indicated in the drawings.

These all go to a storm structure. Just think about it—when we get a big rain, you do not want to flood the sanitary system with the additional water coming from the roof of the building.

You want to have it diverted elsewhere. So there is a storm structure referenced here. You can see that it states "approximate location."

Up here we have another storm system, where it comes down and flows to a storm structure. This note is essentially saying “confirm location.” One thing we need to know is that the civil engineer is responsible for the civil infrastructure on the entire property.

The plumbing engineer is responsible for the plumbing within the building itself. Right here is one of the storm locations we mentioned earlier. We have a sanitary pipe that crosses here, which eventually connects to the city's sewage treatment system.

This drawing indicates that you should confirm the manhole location from the civil drawings, as all of the sanitary waste will be discharged into this manhole. If we look at the drawings in general, you will notice that specific line types represent different kinds of pipes. There are keynotes over on the right-hand side.

At the end of the lines, you will find cleanouts. The pipe sizes are labeled. You will notice that the pipe sizes start off small and get larger as more fixtures connect to them.

This is typical throughout. All of this then feeds into the system, which eventually connects to the manhole. On the right-hand side of the building, a similar layout is shown.

Again, as we zoom in, you will see the storm lines, the sanitary lines, and there they are. A four-inch line feeds into a six-inch line. These drawings require close attention when following and tracing the actual plumbing lines.

But if you begin your review down here at the underground plumbing, you will begin to understand how the systems above work together as one collective system. Let's go on to our next drawing.