Hi I am renting an old HDB unit. One of the taps is leaking (dripping) and before I do the repairs, want to kill off water supply to the whole unit. Attached pic is what the water supply pipe arrangement outside my unit looks like.. The shaft that sticks out (circled in pic) is grooved. There are no other valves available. Am I supposed to turn the shaft using a wrench to cut off the supply? Or get some proper valve handle that will slot into the grooves of the shaft and then turn using that? Checked the staircase landing and that has only a single big red shutoff valve. Probably for the whole floor.