Originally, light was to be provided in the mansion by using carbide gas, but near the end of construction, Paintsville received electrical service. The plans for the mansion were changed to include electrical wiring. The mansion was also designed to include running water, by pumping water from a well to a cistern and then to the house as required. Rain water from the gutters went into the cistern and in turn to the house also. Construction of the mansion was completed in December 1912 with costs in excess of $250,000 ($ in dollars). Mayo Mansion was added to the National Register of Historic Places on May 3, 1974.