Can I replace my shingle driveway with a non-porus tarmac one without planning permission?

I have a shingle driveway which I guess is 'permeable' and would like to change it to a non-porous tarmac with a surface dressing with grated drainage connecting to the existing downpipes. I've read all there is online. From what I gather there is no need for planning permission if you replace a driveway with a permeable solution. What I can't figure out is if I install the drainage connecting to the down-pipes, does this suffice? I'm not sure where the down-pipe water goes... if it goes to an existing soakaway in the garden - yay! no planning needed, ... if it goes to a public drain - boo, planning needed, I think.