We’ve all heard the saying, crap flows down hill. A simple principal related to gravity and the known tendency of water to flow from a high point to a lower point. That is how the drains in our homes operate; by gravity. When gravity is against us, a pump is installed. Yes you can also push crap up hill.
While gravity is reliable as rain, unless you live in California, drains are not. Or perhaps I should say people. Drains are reliable, as long as people install them correctly and more importantly use them properly. Since we humans tend to be, well human, screw ups are bound to happen. Therefore, drains are constructed with ways to fix these occasional mistakes.
With domestic waste drains, clogs are the problem. I’m sure a stopped up sink has happened to most everyone at one time. Or worse a clogged toilet. By far the nastiest of all is a clogged main where the entire house system is plugged. Nothing can be drained off from any fixture. The plumbers solution is not extra strength Draino, but to use a snake inserted into the clogged pipe through a clean out. A clean out is simply an access into a drain pipe in the domestic waste drain system. Building codes state the locations where clean outs should be installed.
The DIYer or the general contractor are not usually aware of the need for clean outs or where they should be located. Couple that with a lack of permitting, which means no inspections and spotting the work of an uninformed amateur becomes easy. Sometimes even comical.
Take for example this drain from a half bath squeezed into what looked to be a old pantry. No cleanout in sight. And that annoying floor joist that was blocking the installation of the pipe. It was just cut right out of the way.
Sometimes it seems even the plumber has an off day. Or two. Here we have the main domestic waste pipe where it exits the house through the foundation floor to the street. As far as I could tell, this was original work in a house that is about 25 years old. Not only was a clean out absent here, but I could not find one anywhere in the entire house!
While the pipes in your home may look uncomplicated, there is specific knowledge needed to put them together properly. Water will flow through an incorrectly installed drain, but it can become problematic when the inevitable clog occurs.
And where will be the "plumber" who installed it be then?