Wastewater & Sanitation

3300–1300 BC

Indus Valley Civilization built public water supply and sanitation systems during the Bronze Age

Settlements of the Indus Valley Civilization in Asia developed organised water supply and drainage infrastructure. This is cited as one of the earliest examples of urban sanitation provision.

800–735 BC

Ancient Rome built its first sewers, including the Cloaca Maxima draining into the Tiber

Rome's early sewer system used stone and wooden drains to collect and remove wastewater from populated areas. The approach conveyed raw sewage to a natural water body where it would be diluted, establishing a model of urban drainage that persisted for millennia.

1990–2015

Joint Monitoring Programme reported open defecation falling from 38% to 25% globally

The JMP 2015 report recorded substantial reductions in open defecation over the MDG period, though 946 million people still practised it. By 2015, 82% of the urban and 51% of the rural population used improved sanitation facilities.

1998

DFID issued a guidance manual on water supply and sanitation programmes defining sanitation

The UK development agency set out a working definition of sanitation for programme design. It contributed to the formal vocabulary used by donors in the sector.

2000–2002

United Nations developed the Millennium Development Goals with a sanitation target

Through the Millennium Summit in New York in 2000 and the World Summit on Sustainable Development in Johannesburg in 2002, the UN set goals for poverty eradication and sustainable development. The sanitation target aimed to halve by 2015 the number of people without access to potable water and sanitation relative to a 1990 baseline.

2006

JMP and UNDP Human Development Report documented slow progress on the MDG sanitation target

Monitoring showed a large gap between target coverage and reality. The finding drove international attention to the lagging sanitation agenda.

December 2006

UN General Assembly declared 2008 the International Year of Sanitation

The declaration responded to slow progress towards the MDG sanitation target. It was intended to raise political attention and investment in sanitation globally.

2020

Researchers estimated methane emissions from non-sewered sanitation at 377 Mt CO2e per year

The estimate put non-sewered sanitation systems at 4.7% of global anthropogenic methane emissions, comparable to emissions from wastewater treatment plants. It linked sanitation infrastructure choices to climate outcomes.

2018

Researchers compared lifecycle costs of full sanitation chain systems in African and Asian cities

The study assessed the whole sanitation value chain rather than individual facilities in developing cities. It informed cost comparisons between sewered and decentralised approaches.

2016–2017

Joint Monitoring Programme defined the sanitation ladder and the term 'basic sanitation service'

The ladder ranks service levels from open defecation through unimproved, limited and basic to safely managed. It created a common measurement framework for comparing sanitation capability across countries.

2016

United Nations replaced the MDGs with the Sustainable Development Goals, including SDG 6

SDG 6 set a target of clean water and sanitation for all by 2030, broadening the ambition beyond the MDG halving target. Sanitation thereby became a standalone global development priority.

2015

Bill & Melinda Gates Foundation published its sanitation strategy 'Building demand for sanitation'

The portfolio update set out the foundation's water, sanitation and hygiene priorities. It also funded India's Sanitation Capacity Building platform from 2015 to 2022 to help towns plan decentralised sanitation solutions.

2011

Bill & Melinda Gates Foundation launched the Reinvent the Toilet Challenge

The initiative funded research into safer and more effective ways to treat human waste. It sought technologies suited to settings without sewer networks.

2010

UN General Assembly recognised the human right to water and sanitation

The resolution established sanitation as a matter of rights rather than merely service delivery. It reframed national obligations around access to safely managed sanitation.