This part of the standard series DIN EN 806 specifies requirements for the operation and maintenance of potable water installations within buildings and for pipework outside buildings but within the premises in accordance with DIN EN 806-1. The recommendations given in the standard are primarily intended for the purpose of correct functionality of potable water installations and therewith to ensure a stable continuous water supply, but also for maintenance of the operating conditions for compliance with the water quality specified in national regulations - in Germany in the Trinkwasserverordnung ("Drinking Water Regulations") - and for avoidance of adverse effects to equipment of the water supplier. The statements on the necessary documentation are followed by principles regarding operation, interruptions to operation, disconnection and resumption of supply and possible faults (insufficient water supply, impairment of water quality, noise emissions, amongst others). Alterations, extensions and refurbishments of potable water installations do not only necessitate accessibility to the respective installation components, but also additional requirements for the operation, inspection and maintenance. The annexes attached contain specifications for frequencies for inspection and maintenance of components of potable water installations and for inspection and maintenance procedures, amongst others, for protection units, inline hot water supply tempering valves, pressure booster pumps, fire fighting installations, pipework and water meters. Specific inspection and maintenance procedures in accordance with the relevant product specifications apply for water conditioning devices. Working Committee NA 119-04-07 AA "Häusliche Wasserversorgung" ("Domestic water supply") provided crucial support for this standard, which has been prepared by CEN/TC 164/WG 2 "Internal systems and components". By preparing this part, the development of the DIN EN 806 standard series has now been completed for the time being. At the moment there is no evidence that there are intentions to continue the series. Due to the large time frame in which the individual parts of the standard have been prepared, future tasks - from the present point of view - will be limited to compensation of lack of precision and errors of the first compromises.