It shall be unlawful for any person to throw trash, rubbish, sticks, stones or any other substance into the storage tank or reservoir or other parts of the water system and it shall be unlawful for any person to throw or place any trash, rubbish or any other substance on the grounds surrounding the buildings of any part of and pertaining to the city water system and known as the pumping station lot. (`86 Code, § 21-40) Penalty, see § 1-99