In 1901 Rolla Wells became the thirty-fourth Mayor of St. Louis.
Rolla Wells was elected and inaugurated in April, 1901. On taking office Wells sold his local public utility holding company and steel stock, so that there could be no 'conflict of interest' involved in his administration. 'New St. Louis' was the slogan of his administration. He headed the City's Government during the Louisiana Purchase Exposition, known as the St. Louis World's Fair of 1904. In this capacity he welcomed visitors to the City from all over the world.
It was during Wells' administration that the City Water Department accomplished clarification of the water supply. Previously St. Louis had been known for its cloudy drinking water. Milk of lime was used with iron sulphate in the first attempts to clarify the water by means of chemical coagulation. This process, then in experimental stage, was introduced in the Spring of 1904. This progressive step was highly desirable at the time because the World's Fair was about to open and bring many visitors.
During Wells' administration the City bought Fairground Park for $700,000. City playgrounds and public bath houses were constructed. City planning activities were started. Many of the main streets were hard surfaced. In 1906 a $2,000,000 bond issues was voted by the people of the City to build the Municipal Courts, Jail and Children's buildings. These were completed during later administrations.