I have installed these on 2 round toilets. I don't think that really matters though. There is a line the diameter of an ice maker line that you would run to the sink for hot water. I did that in one restroom but just hooked that up to the cold water line in the other restroom. That way, in the winter, I have 10 feet of water at room temperature in that line and it's not just freezing cold water. I find that I don't use the hot water that often because you have to run the bidet on wash or turn on the hot water at the sink to give the hot water time to reach the bidet.. But the room temperature water is fine.