Water and sanitation, where our guest treats sewage

How much is treated: three estimates

• CPCB. The Central Pollution Control Board's national inventory, reported in 2021, found that sewage treatment plants treated only 20,235 MLD of the 72,368 MLD of sewage generated daily⁶.
• NITI Aayog and the ministry. A parliamentary committee review noted that a 2022 NITI Aayog report put the share of wastewater treated at 28%, against 43% by the Housing Ministry's estimates⁷.

Sewers, septic tanks and sludge

Of India's 11.3 crore urban households, only 3.5 crore are connected to sewer networks, a parliamentary committee review found². Another 2.9 crore depend on septage-based systems such as septic tanks, and 68% of septic tanks surveyed were not lined properly³.

Treatment produces its own waste. India's sewage treatment plants generate nearly 8,000 tonnes of dried sludge a day and faecal sludge treatment plants about 32 tonnes, and the committee said resource recovery remains at an emerging stage⁴.

Faecal sludge plants are not always used once built. Across more than 700 towns, Uttar Pradesh has built over 50 faecal sludge treatment plants, but as of April 2025 at least 18 were operating at just 20% of capacity, according to a Centre for Science and Environment report cited by Down To Earth⁸.

Reuse of treated water

Against a treatment capacity of 22,891 MLD, 6,013 MLD of treated wastewater (26%) is being reused, a parliamentary committee review found⁹.

In Bengaluru, of the roughly 2,250 million litres of wastewater generated daily, 77% is treated but only 14% is reused, Citizen Matters reported in September 2026¹⁰. WELL Labs estimates the city has at least 4,000 registered apartment sewage treatment plants, of which around 2,500 are operational¹¹.

Rural India: greywater and sludge

• Greywater. The Jal Shakti Ministry says nearly 65% of household wastewater in rural India is greywater¹².
• Liquid waste. As of 16 December 2025, over 5.41 lakh villages had arrangements for liquid waste management under Swachh Bharat Mission-Grameen, according to the Jal Shakti Ministry¹³.
• Sludge plants. Swachh Bharat Mission-Grameen's dashboard counted 2,303 faecal sludge management plants created in rural India as of January 2026¹⁴.
• Village status. As of January 2026, 97% of India's villages were ODF Plus and 84% were ODF Plus Model villages under Swachh Bharat Mission-Grameen; first verification of Model status had been completed in 72% of villages¹⁵.

Cities by sanitation status

Indian cities by sanitation certification, as of 19 Nov 2025

As of 19 November 2025, 4,692 Indian cities were ODF, 4,314 had achieved ODF+ and 1,973 had reached ODF++, the level at which faecal sludge and sewage are safely managed, according to the government⁵.

The people who clean sewers

Official figures given to the Lok Sabha in August 2026 show 498 sanitation workers died while cleaning sewers and septic tanks in India between 1 January 2019 and 30 June 2026, including 47 in 2025, according to National Commission for Safai Karamcharis data¹⁶.

The global picture

Globally, 56% of household wastewater was safely treated in 2024: of an estimated 332 billion cubic metres generated, only 185 billion was safely treated, according to the UN's 2026 SDG report¹⁷.

3.4 billion people worldwide still lack safely managed sanitation, including 354 million who practise open defecation, according to WHO and UNICEF¹⁸.

A regulator asks for online monitoring

In June 2026 the Goa State Pollution Control Board approved guidelines requiring all sewage treatment plants in hotels, hospitals and residential complexes to install online IoT-based equipment monitoring within six months, The Goan reported¹⁹.

Startups bringing software and robots

• Software. Watertech startup DigitalPaani raised Rs 22 crore in a round led by Navam Capital in September 2026; its AI- and IoT-powered software platform serves more than 95 facilities across India that together treat over 150 million litres of water a day, Inc42 reported²⁰.
• Robotics. IIT Madras-incubated Solinas Integrity, which builds robotics and AI systems to inspect, clean and digitise underground water and wastewater infrastructure, raised $5.5 million in a Series A1 round in August 2026²¹.

Development lenders

• Bengaluru. The World Bank approved a $426 million loan in June 2025 for a Karnataka water security programme that will build nine sewage treatment plants and give over 100,000 Bengaluru-area households their first sewerage connections, with treated wastewater reused for industry and groundwater recharge²².
• Chennai. The Asian Development Bank approved a $230 million loan in July 2026 to modernise Chennai's water supply and sanitation, including upgrading 38 sewer pumping stations, benefiting 4.5 million residents²³.

Decentralised plants and new models

Delhi's Expenditure Finance Committee approved Rs 31.4 billion in April 2025 for 27 decentralised sewage treatment plants, and the Delhi Jal Board approved Rs 6 billion for 11 more in August 2025, Indian Infrastructure reported²⁴.

Hyderabad's Megaliter Varunaa raised Rs 15 crore in seed capital in October 2025 for a zero-capital-expenditure, subscription-based model that turns sewage treatment plants into circular water utilities²⁵.