Boards of Guardians were given certain powers in connection with sanitation under the Nuisance Removal Act of 1855. Following the Public Health Act of 1872, they formed the rural sanitary authority for those parts of the union which were not included in urban sanitary districts. In the case of the Pontypridd Union, the rural sanitary authority covered all of the union except for the urban sanitary districts of Pontypridd and Mountain Ash; from 1877 Ystradyfodwg was also excluded.
The rural sanitary authority was responsible for sewerage and water supplies, control of nuisances and other public health matters.
In 1895, rural sanitary authorities were replaced by rural district councils following the Local Government Act of 1894.