I have a 5 stage IPC EAGLE RO electric system that I use regularly on commercial and residential. I have on occasion had to hook up to water that was comin out HOT. I'm not sure how hot but I'd say at least 150. I might have that water running through for about 2-3 hours. I called IPC EAGLE and talk to their tech guy and he wasn't totally sure but he didn't think it was a problem. The only thing he thought might happen is it would possibly shorten the life of the RO membrane. I only have about 20,000 ga on these cartridges so it will be a while before I know if they are going prematurely. Does anyone have any experience or knowledge running hot water through their systems? Thad, any thoughts?