I doubt there is a shut off value to this particular faucet. The whole, as you can see, is just enough to fit the valve. In fact, I had to chip away a few pieces in order to have enough room to remove the retaining clip. I bought this house a year ago, and i think the bath was remodeled couple years before that. Based on the fact that the size of this hole, I would guess the remodeler was too short sighted to design so that it is serviceable.....

Also, the other side of the wall is the master bath.