The sewer system for your home or business can be crudely divided into two sections; the internal sewer system and the external sewer system.
The internal system is made up of all of the drains in your plumbing system, which work to carry waste and wastewater away from your appliances and fixtures.
These drains manage a significant amount of used water and solid materials on a daily basis. And, that makes them susceptible to a drain clog or build up.
The drains in your home or commercial building are all connected to the main sewer line; this would be considered the external section of your sewer system. The main sewer line is configured to carry used water and waste out to the municipal sewer line.
You pay a monthly fee to be connected to the municipal sewer line, and it is responsible for carrying the collective waste from all drains in your home and the main sewer line all the way to the closest treatment plant.
While the sewer system as a whole seems fairly simplistic, the materials that it manages are far from it, and that means that clogs and leaks can happen.