Practically speaking you could change the elbow coming out of the wall for a Tee and then connect the rainwater into the top of it.
Regs wise, I believe that even in a combined system the rainwater and soil should be separate until they reach the sewer. Otherwise if there is heavy rain or leaf fall from the rainwater then you risk the pipe clogging and the rainwater coming out of the toilet...
So I wouldn't do it.
Regs wise, I believe that even in a combined system the rainwater and soil should be separate until they reach the sewer. Otherwise if there is heavy rain or leaf fall from the rainwater then you risk the pipe clogging and the rainwater coming out of the toilet...
So I wouldn't do it.