I am renovating my 1930 Craftsman Bungalow (small) bathroom. The toilet drain is too far away from the original wall for a modern toilet to sit without having about a 5-6 inch gap behind it. The previous owner renovated once before and built out the wall to use a modern toilet on the old toilet drain.

I want to maximize space and move the toilet back to the original wall, but that will require a new toilet drain drilled through 4" concrete. I'm not sure what is the best way to do this, especially considering I am saving the original tile flooring. The new toilet luckily fits over and hides the old drain, so if this works I will be in business!

How would I best drill a 3-4 inch hole through this concrete? I have a basement under this floor so the plumbing part wouldn't be a problem.

Thanks in advance!

How would I best drill a 3-4 inch hole through this concrete? I have a basement under this floor so the plumbing part wouldn't be a problem.
You would go down to your local rent all and rent a core drill,(see image) in the size that you'll need. Good luck, Tom