Where a sewer is not accessible to a dwelling there shall be a privy-vault located in the yard thereof, and constructed in accordance with the laws, ordinances, and rules of the Bureau or Board of Health¹ relating thereto. Such privy-vault shall be cleaned to the bottom whenever the contents come within three feet of the level of the ground outside, or within three feet of the floor of the privy-house, if such floor is below the level of the surrounding ground, and shall be corrected with lime by the tenant or occupant of the property whenever it becomes foul.