Water is leaking from basement toilet. help
If water is coming up through the pipe then it is because either your sewer is clogged, you septic tank is full or the leaching field has failed. What you are seeing is a sewage backup. It could be ground water entering your septic tank, or it could also be sewage from elsewhere in the house.  The basement toilet is the lowest drain in the house and this is where the water comes out.

You should check your tank.  If it's full of liquid then there's an issue with your leaching field. If its full of solids then it needs to be pumped. If it is not full, then there is a clog in your main sewer and that needs to be cleared in order for the contents of your drain pipes to empty.