I am also stuck in Chorrol.
If you are where the chests are stacked up, that is the not the sanctuary entrance, it is the cave-in opening from the mine that you can get to from outside the city. I doubt that that way will ever be opened.
There is a hole to look into the sewer from the mine side but not out from the sewer side. If you search that area you should find a vial of "Night Mother's Blood" I have not found what it is for yet.
The sanctuary is past the knocked down DB door with a hand on it. There seems to be two locked gates that lead further into the sewers and I have not found how to open them.
Evidently, there is a lever in addition to two wheels that open doors. I have been through the sewers at least six times and I cannot find anything like a lever or anything that acknowledges your touch and might activate.
I know others have had problems as well, but then they find the lever and post back that it was "right under their noses" and they don't know how they missed it.