well its not a rouge nodraw, cuz just above the surface is a small hall, that I needed to build, like well, for the areaportal. the tunnels leads into a room underneath the exterior of the map and is closed with area portals. the water texture i am using is Water_well. I do have water on seperate heights and in seperate areas that arent linked by anything other than an areaportal seperation (they are in the same area). The tunnel is in the Outer area leading into a room, similar to Well, but the room the tunnel enters needs a areaportal to close the area, if not it leaks through the tunnel.
I guess leak for the title was a poor choice of words but it really is what happens, there. The effect is similar to a nodraw leak but there is no reason for it. the tunnel enters a room where there is a ceiling and is sectioned off in an area similar to the center CP of well. the room size is different and there are less areaportal brushes but the concept is very much similar to well. The water is outside and leads to inside.
I portaled off the entire tunnel and the subterranean exit now shows nothing but sky box. where as the base exit is still as it should be and the ramp exit has a similar leak.
pics included to show what I mean.