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Indicator 6.3.1 “Proportion of domestic and industrial wastewater flow safely treated”

Target 6.3 seeks to halve the proportion of untreated wastewater discharged into our water bodies – this page explains why and how to monitor progress towards the target.

The indicator at a glance

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.

The household component includes both sewage and faecal sludge, treated on-site and off-site, and is monitored as part of the sanitary chain with direct links to indicator 6.2.1 on access to sustainably managed sanitation services.

The services and industrial premises are defined based on the International Standard Industrial Classification (ISIC).

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).

Available support 

The World Health Organization (WHO) and United Nations Human Settlements Programme (UN-Habitat) are the custodians of indicator 6.3.1. For any enquiries about available support, please contact their helpdesk.

Guidance on data collection and reporting

Online support

  • Helpdesk (email, phone, video conference).
  • Training course (under development).
  • Kobo toolbox for wastewater assessment (under development).

Face-to-face support

  • National workshops in selected countries.
  • Regional workshops (League of Arab States, Commonwealth of Independent States).

Data and progress reporting


Why monitor wastewater treatment?

Wastewater utilities often collect data on wastewater collection and treatment for management and regulatory purposes.