In the Strategy , increasing “ sustainable first time access” refers to access to an improved water source that is gained by previously unserved populations . improving the “ quality of sustainble water supply services” referes to increasing existing access to and improving the quality of an already improved water supply 21 For both first time access , and improved access, methods for ensuring the sustainability of water quality in the long term should be incorporated into progam design . this may imclude developing monitoring systems to ensure that water quality , as well as water supply ,is sustained at acceptaable levels .