The board of supervisors hereby finds and declares that the accumulation upon streets, sidewalks and private property of rubbish, garbage, grass, weeds and other rank growths may cause serious fire hazards, provide a harbor-age for rodents and a breeding media for insects; that such wastes by their presence may injuriously affect the health, safety, comfort and welfare of persons in the vicinity thereof; and that such wastes produce unsightliness resulting in depreciation of property values and the comfortable enjoyment of life. (Prior gen. code 3-150.0)