Scope: This International Standard specifies the elements of drinking water and wastewater services of relevance and interest to users. It also provides guidance on how to identify users' needs and expectations and how to assess whether they are being met. The following are within the scope of this International Standard: the definition of a language common to the different stakeholders; the definition of key elements and characteristics of the service to users; the objectives for the service with respect to users' needs and expectations; guidelines for satisfying users' needs and expectations; service to users assessment criteria; introduction to performance indicators; examples of performance indicators. The following are outside the scope of this International Standard: methods of design and construction of drinking water and wastewater systems; the regulating management structure and methodology of operation and management of activities relating to drinking water and wastewater services, including contracting; topics relating to the system inside buildings. NOTE 1 This International Standard, ISO 24511 and ISO 24512 comprise a series of standards addressing water services. It is therefore advisable to use these three International Standards in conjunction with each other. NOTE 2 The list of terms and definitions in Clause 2 is common to this International Standard, ISO 24511 and ISO 24512. NOTE 3 Annex A contains three tables of correspondence between equivalent terms in English, French and Spanish.