Ahh yea didnt think about the city side and the pressure. what if you turned down the city pressure with a valve? then fed the line into the city line. just run the 1/2 or 1/4 inch tube whatever it may be into it and let it drip in like it comes out of the waste side of the ro their is very little pressure on the ro side. i would wonder if it not having very much pressure if it would even work.. Mike i hope im not frustrating you, not meaning to, im just wondering.