HI
IT SOUNDS LIKE YOU HAVE FOUND YOUR FOUL DRAIN RUN, YOU ARE NOT MEANT TO CONNECT SURFACE WATER TO THIS PIPE YOU ARE MEANT TO HAVE A SOAKAWAY TO DISPOSE OF SURFACE WATER, YOU CAN NOT LET IT DISPERSE ONTO THE PATH/ROAD IF YOUR DRIVEWAY FALLS AWAY FROM YOUR PROPERTY.

The pipe will be either fowl drainage or what is known as top water. Top water is classed as rain water. They generally have separate systems and are not very often combined systems. We would recommend finding manhole and checking. We would not recomed piping downpipe into the system until you have established which pipes are which. Hope this helps. Darren.

The other pavers is correct if it is the foul drain. If it's the storm drain from your house then you can connect to it. Follow the direction the pipe its coming from or going in and there will be a manhole (disconnecting manhole, theres normally 2 per house hold on newer builds)Somewhere on that line. Lift the manhole lid , flush your toilet , if the water comes through that manhole then you know that's the foul drain. If not then it's the surface water drain which you can connect to as long as you do a proper connection

The pipe of 100mm is dranige water you don’t need too connect the driveway drainage to that pipe because the rain water is separate pipe that pipe maybe is toilet pipe which you can see by lifting manhole cover but the driveway drainage you can connect to soak away if no any rain water pipe close to driveway