Central drinking water supply – Guide lines regarding requirements for drinking water, planning, construction, operation and maintenance of plants – Technical rule of the DVGW
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 10/01/2000

Central drinking water supply – Guidelines regarding requirements for drinking water, planning, construction, operation and maintenance of supply plants
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 02/01/2017