Continuing the Tracking Climate Financing series, where we present specific climate finance projects featured in our tracker, we continue with notable Brazilian projects. Today’s selection is the Tietê River Cleanup Program Stage IV.
What is the Tietê River Cleanup Program Stage IV?
Approved in October 2018, the project is the most recent phase of a continuation of the program to clean up the Tietê River—a river that runs through São Paulo and has historically been marked by urban and industrial pollution—which began in 1992 as a partnership between the Inter-American Development Bank and the State of São Paulo, through the São Paulo Basic Sanitation Company (SABESP).
Figure 1: Stages of implementation of the Tietê Project in the RMSP
Source: SEBASP, 2008
In short, the project aims to contribute to improving environmental and sanitary conditions in the Upper Tietê River basin, in the São Paulo Metropolitan Region, thereby reducing the organic load from domestic effluents discharged into the Tietê River through the sustainable expansion and optimization of the sewage collection, transportation, and treatment system.
How does the financing work?
Mitigatory in nature, this project, which was conceived as a continuation, was financed through a loan from a flexible financing line from the Inter-American Development Bank in the amount of USD 300,000,000.00, with a national co-financing counterpart of USD 200,000,000.00. The distribution of this financing occurred in three components: (i) sanitary sewage works responsible for financing sanitary sewage, including the construction of collection networks and respective household connections, pumping stations, trunk collectors, and expansion of treatment plant capacity; (ii) operational and institutional sustainability, subdivided into three areas: strengthening Sabesp’s capacity in the management of sewage systems, developing and implementing projects that introduce innovative operational technologies in the field of water and sewage services, and providing structural support to Sabesp to meet the requirements of the regulatory body.
Table 1: Distribution of investment values in the components of the Tietê IV Program
| COMPONENT/CATEGORY | SCHEDULE US$ x 1000 | ||
| Bank | Sabesp | Total | |
| Component 1 — Sanitary sewerage works. | 290.600 | 187.400 | 478.000 |
| Component 2 – Operational and Institutional Sustainability | 7.000 | 7.000 | 14.000 |
| Management Support, Monitoring, and Evaluation | 2.400 | 5.600 | 8.000 |
| GRAND TOTAL | 300.00 | 200.000 | 500.000 |
Source: Prepared internally based on data provided by Sabesp, 2018.
How is the project progressing?
The project is currently still in the implementation phase, with the latest report provided by the IDB published on January 0, 2026, covering the progress of the project in the first half of 2025. As of the date of the document, IDB transfers exceeded 51% of the total project value, demonstrating consistent financial execution. Overall, the project has managed to make progress in increasing the number of households served to 78%; effectively reducing the organic load by 568 t/day; and providing technical and regulatory training for professionals working in the field. However, there are still obstacles such as the pace of physical works, which are relatively behind schedule, although the contracts are active and in progress; expansion of treatment capacity, which is still in its early stages; and weaknesses in the social management of the project. In summary, the program has been implemented with measurable results, especially in terms of sanitation coverage and pollution reduction.
REFERENCES
SÃO PAULO (Estado). Companhia de Saneamento Básico do Estado de São Paulo – SABESP. Programa de Despoluição do Rio Tietê – Etapa IV: Avaliação Ambiental e Social (AAS) e Marco de Gestão Ambiental e Social (MGAS). São Paulo, 2018. Disponivel em: https://www.sabesp.com.br/site/uploads/file/projeto_tiete/projeto_tiete_versaofinal.pdf. Acesso em: 01 fev. 2026.
ANCO INTERAMERICANO DE DESENVOLVIMENTO (BID). Tietê River Cleanup Program, Stage IV (BR-L1492): PMR Public Report – First Period Jan–Jun 2025. Washington, D.C., 2025. Disponível em: https://www.iadb.org/en/project/BR-L1492 . Acesso em: 01 fev. 2026.
