It should be interesting to find out. Our house built in 1967 with septic field had the cement style perimeter drain tiles circling the house and running out to the drainage ditch along the road. When the ditch was filled in they were supposed to connect this to the storm drain system. We would have to get a permit (eventually) to connect remove the septic system and connect to the sewer drain system.Good point. I’ll check in with the architect.
Well the hollow tiles may well have been emptying into the storm ditch but the people doing the work, if they even found it, didn't connect it to anything. We discovered that when we finally removed the septic field and had the cement septic tank broken down and filled in. The house was then connected to plastic drain pipe and run down hill to the road to the sewage connection.
But here's the interesting thing. At the back of the house where essentially the ground level was 8' above the basement level (front of house is level with the ground) there is a floor drain right by the washing machine pipes a industrial sink drain and beside that a sink/shower/toilet. The industrial sink, shower, bathroom sink and toilet all drain into the sewer drain.
The floor drain went out the back of the house into the perimeter drain through a trap. At the worst of the wet weather I had a plastic pipe stuck into that floor drain and packing around it so we wouldn't have the basement filling with water. The water in the vertical pipe was about 8" above the concrete floor level.
When the tiles were pulled the majority along the back of the house all were full of clay with maybe an 1/8" gap along the top. As the water ran down hill it towards the house it would hit the wall and rise up. Eventually the hydro static pressure was enough for it to move around the house through and along side the blocked drain tiles and out the front area. As long as I had the vertical pipe stuck in there and the shop vac handy for sucking up leakage.
Anyway. I suspect modern code will insist that floor drains in the concrete floor will be tied through a trap to the sewer drain not the storm drain.