Hi Dave,

In my previous experience working at Fresenius Medical Care, we had a mix of patients we were under contract through various hospitals to maintain their equipment. The majority of patients were in single detached homes but also had a good number of patients as well in apartments. Installations in apartments definitely limit the final set-up. Most of what I have seen have been under the sink vanity connections with a a PVC drain open on one end and connected to the P-Trap under the sink. 

As Ron mentioned, it may be likely that a sub-panel may be required for older units. I honestly do not know if there was much consideration regarding the building drains or not as I was not involved at that level for most of the hospital installations, so there may be hurdles regarding code as well.. 

The one thing that I would recommend would be to have a Flood Stop device in place so that if the RO or hemo machine were to leak, the damage would be minimal (the device shuts off the water supply) and the patient would be notified of the problem via an audible alarm that there is in fact a problem.