Today, I mowed over the septic system's leach field with my BX 2230, but I didn't go over the area where the tank is. I felt fine about it. After reading all these posts, I had a conversation with my dealer. I went in there to talk to them about a tooth bar and a chain saw (bought a new Stihl saw to replace my pos Poulan). Anyway, the sales guy was out at my property when he delivered the tractor, and remembered my septic system. He said he didn't think it would be a problem with my weight of tractor. I am not suggesting his word is gold, but he doesn't strike me as someone who talks about things he doesn't know about. So, with the many responses I've gotten here (thank you) and his response, I feel comfortable with it. Its a large area on a good-sized hill and would be a drag to mow it with the push mower.