Hans Yost Creek is designated as an impaired waterbody for its entire length. The causes of the impairment are metals and
pH and the probable source of impairment is
abandoned mine drainage. There are two abandoned mine discharges in the creek's watershed. One is known as the Moser Mine Pool Discharge and enters the creek in its upper reaches. The estimated flow of this discharge is 0.259 million gallons per day. The other is known locally as Rattling Run and is formed from the Collapsed Tunnel Discharge and the Buck Mountain Vein Overflow Discharge. This discharge enters the creek in its lower reaches. The average
discharge of Hans Yost Creek above the Moser Discharge has been estimated to be 0.259 million gallons per day, while below the discharge, it has been estimated at 0.518 million gallons per day. Above the Rattling Run discharge, the creek's discharge was found to average at 1.49 million gallons per day, while below the discharge, it was 3.59 million gallons per day. In the 1980s and/or 1990s, the
iron concentration in Hans Yost Creek upstream of the Moser Discharge ranged from , with an average of . Below the discharge, it ranged from less than to , with an average of . Above the Rattling Run discharge, the iron concentration ranged from , with an average of . Below this discharge, the concentration ranged between , with an average of . The
manganese concentration in Hans Yost Creek upstream of the Moser Discharge ranged from less than to , with an average of . Below the discharge, it ranged from with an average of . Above the Rattling Run discharge, the manganese concentration ranged from , with an average of . Below this discharge, the concentration ranged between , with an average of . ==Geography, geology, and watershed==