ISO 24521:2016 provides guidance for the management of basic on-site domestic wastewater services, using appropriate technologies in their entirety at any level of development.

ISO 24521:2016 supplements and is intended to be used in conjunction with ISO 24511. It includes the following:

· guidelines for the management of basic on-site domestic wastewater services from the operator's perspective, including maintenance techniques, training of personnel and risk considerations;

· guidelines for the management of basic on-site domestic wastewater services from the perspective of users;

· guidance on the design and construction of basic on-site domestic wastewater systems;

· guidance on planning, operation and maintenance, and health and safety issues.

The following are outside the scope of ISO 24521:2016:

· limits of acceptability for wastewater discharged into a receiving body;

· analytical methods;

· the management structure of sanitary waste/wastewater service activities of operation and management;

· the content of contracts or subcontracts.

ISO 24521:2016 is applicable to both publicly and privately operated basic on-site domestic wastewater (black and grey water) services, for one or more dwellings.