Indicator 6.3.1 tracks the percentage of wastewater flows from households, services, and industrial premises that are treated in compliance with national or local standards.

Data on 6.3.1 are commonly collected by national line ministries and institutions (e.g. for Water, Sanitation, Environment, Health, Public Services, Planning, Housing, Infrastructure, Production), utilities and on-site service providers as well as the National Statistical Office (household surveys and registers of economic activities).