There are has been many stages in drain development over the years, from clay pipes up to modern plastic systems. All types have there positives and negatives.
Drain troubles can be a nightmare, especially on old buildings that have 100 year plus systems that have established gardens with tree's, bushes (roots & drains are best friends) and new modern extensions and driveways added.
Newer plastic systems in new builds have a more efficient design with there clean smooth lines and 3 metre length pipes that just simply fit together with the aid of some lube. The problem occurs when they have not been suitably cushioned and surrounded with sand or small chip stones. The ground surrounding new built houses can and do eventually sink slightly so the cushioning effect helps keep things on the straight and more importantly keeps the joints all in tact.
How do you know it’s blocked in the first place?
Smell !!! Trust your nose, every house has a manhole chamber normally situated on a corner then have a disconnecting chamber at the properties boundary just before it flows in to the main sewer system on the street.
These manhole chambers act as a small septic tank, filing up and storing sewage waste for several hours even weeks and things are flush away normally in the home as per usual.
The pungent smell is the first tell tale sign some things partially or fully blocked. Strongest in the morning times in the home but constant outdoors.
The next tell tale sign is the sink, bath toilet sluggish in draining away.
The manhole covers and traps out doors will be showing signs of sewage overflowing on to paths etc. Time for action.
Start by looking at the last point in the drainage system that is showing signs of sewage. if it's from a trap cover near the building. open the lid.
Now with a rod and a 4" or 5" plunger, insert it into the trap all the way to the bottom, back off about 8 or 10" then make several rapid plunging motions. If it clears you will feel the sucking on the rods as it goes.
If it's from a manhole cover open it. You should see it full with waste. Feel about with your rod and plunger until you feel the access channel, enter the plunger in to the pipe adding more rods as you push them along. When you start to feel the blockage, push back and forth with big long strokes.
A sure sign the blockage has cleared is a sudden drop in the chamber. Remove the rods and let all the backlog flow.
If the sewage is showing at the disconnecting manhole at the boundary. Again open it. If it's an old system there will be a trap in this chamber. Find it with the rods and plunge it several times using a 5" or a 6" plunger. Again you will notice the sudden level drop and feel suction on the plunger as it goes.
If it's a new build drain with plastic pipe. There will be no trap in this manhole. If it's blocked try the the rods in the channel adding as you go alone the pipe. If that fails the problem would more than likely be out in the main sewer (local council).
This is a very basic explanation on drain clearing. There are so many factors and every drain type has a different approach and way of clearing.