Porto's two wastewater treatment plants treated 24,544,212 m³ in 2024, while the city's municipal water company billed 19,411,607 m³ of drinking water that year. In 2025 the plants treated 24,527,613 m³.
Sewers, drains and streams
Águas e Energia do Porto measured infiltration and inflow to its sewers at 18.03% in 2025, well inside its contract target of 27%. The company runs 572.2 km of sewers with 21 pumping stations, alongside a separate stormwater network of 642 km and 85 km of streams, 82% of them culverted.
A resource left unused
ERSAR, the national regulator, recorded 0.0% of treated wastewater produced for reuse in 2022, 2023 and 2024. A flat-membrane pilot at the Freixo plant has produced class A water for non-potable use since November 2022 while ERSAR's figures for those years show no reuse at production scale.
Where the money is going
The plants are the focus of a €4.5 million program reported in June 2026. Freixo's solar capacity is due to rise from 133 kWp to 635 kWp by the end of 2026, and biogas recovery there is expected to be completed in the first half of 2027. Sobreiras received a 387 kWp solar plant in 2025. Wastewater drainage and treatment took €5,186,066 of the company's €13,739,192 investment in 2025.
Compliance slipped
Compliance with discharge requirements was 98% in 2025, against a contract target of 100%, and the four-hour emergency reaction for wastewater reached 87.90%.
How Porto's bulk water supply, governance and drinking water network compare with its wastewater side, and which projects run to 2027, are set out in the full report. The full report, Water Systems Overview: Águas do Porto, is available for USD 499. For a free overview, read the Águas do Porto Utility Snapshot.