Corporation stops shall be located at the ten o’clock or two o’clock position on the circumference of the pipe unless this would result in any part of the service line attached to the corporation to have less than five feet of cover. Where five feet of cover is not available, the location of the corporation may be rotated downward, but no lower than the mid-point of the main to be tapped. Water Department personnel shall make all taps on all department water mains.