william
If the leak persists, before replacing the entire valve, try this. Turn off the water at the house’s main shutoff, then disassemble the problematic shutoff valve without disconnecting the valve from either the water supply line or the line leading to the toilet. Unscrew the handle, the packing nut and the threaded valve stem.
Clean the washers with a cloth and flex the neoprene to try to get it supple again. Avoid gumming up the inside of the shutoff valve; don’t use any pipe dope or plastic tape on the valve stem’s threads. Reassemble the shutoff valve, turn the main house valve back on and check for leaks. If the valve leak persists, turn off the main water shutoff valve, then disconnect the valve and replace it.
