I've noticed this has been going on for a very long time, even during periods of very dry weather. As such I'm of the belief that it's unlikely storm water in the basement. The fixed piping imbeded in the sidewalk leads me to think this might be an illegally installed permanant grey water discharge. (It should also be noted that a laundramat operates at this location.) A sample of this discharge should be collected and examined by the health department and/or watershed association, as it goes straight to the storm sewer.

Still nothing on this?

Maybe this is something that should be reported to the sewer auth 610-270-3190. we had water coming up out of the grass next to the sidewalk and called. they were quick to come out and take a look to see if it was them.