This sandstone fountain was erected in 1686. Its state of decay is analyzed. The State Institute for Restoration in Prague concluded that a complex cleaning program was needed to open up the pore structure of the stone, replace the old cement fillings, and protect the stone surface against both fountain water and air pollution. Six types of poultice to disperse incrustations were tested, their active bases compared; graphs show how much gypsum loss occured with each use. The consolidation method adopted resulted from long experience; the techniques and materials of consolidation and final hydrophobic impregnation are given along with an evaluation of the results. The fountain has been re-used for four years with no new evidence of deterioration. Acknowledgements are appended.