yep, sewer lines go all the way to beneden. Water top. Zijn is pumped to a pressure check valves at different levels, the pressure is too high to avoid.

A vent connects all sinks and toilets goes all the way to the roof, like houses.

All drains connect to a huge line that goes to a sewer main under the building. This is why a “j” trap under the sink have.

There is always a layer of water that leaks in sewer gas remains down the sink drains “pop-up plug ‘hole.

Apartments have one or two boilers per floor, commercial buildings, probably by 2 or 3 floors. To create pressure on the lawn sprinklers just have to keep reducing the size of the pipe, the farther you go out. ..

But skyscrapers I’m sure they use a pump system of different stages of the main inward

theres one of the main sewer pipe for every 5 levels or dependent in the design and theres a transfer floor for every 15 floors.ussualy it safe from sewage treatment plants before they release it into the public sewer line