EYATH S.A.

About the Utility

EYATH provides water supply and sewerage services to more than 1.2 million citizens in the greater Thessaloniki Urban Area. Listed on the Athens Stock Exchange since 2001, it remains under state control: the Hellenic Republic holds 50% plus one share directly and a further stake through the Hellenic Republic Asset Development Fund. The company runs the urban water cycle from river, spring and groundwater sources through treatment and distribution to sewer collection and wastewater treatment. Its financial cost and tariffs are approved by the Regulatory Authority for Waste, Energy and Water. For the first regulatory period, covering 2025 to 2029, approved tariffs stay unchanged unless revised through an extraordinary review of financial cost.

Water System

EYATH draws on three sources: the Aliakmonas River, treated at the Thessaloniki Water Treatment Plant, the Aravissos springs in Pella, and boreholes in the plain of Thessaloniki. In 2025 the plant supplied 48,337,745 m³ of drinking water for consumption from Aliakmonas surface water. Supply reaches around 522,261 water connections, backed by reservoirs with 218,000 m³ of useful capacity. Losses remain a central operating issue: non-revenue water was 26.84% that year, against a target of halving it by 2030. EYATH is replacing older meters with volumetric and smart digital units, and its drinking-water laboratory is accredited.

Wastewater System

EYATH also collects and treats the metropolitan area's wastewater. The Thessaloniki Wastewater Treatment Plant serves the central and western zones and is designed for 296,000 m³ a day, while the Aeneia plant, opened in 1997, serves eastern tourist areas. Together the plants treat 60.5 million m³ of wastewater a year. Thessaloniki's network includes combined sewers, and EYATH is working with Siemens on artificial intelligence and IoT tools to prevent overflows and floods. Treated water produced by the Sindos biological treatment station currently discharges to the Thermaikos Gulf.

Investment & Priorities

EYATH reports €14.3 million of investments completed in 2024, with further works contracts tendered or awarded. For 2025 to 2029, the regulator's decision records a submitted plan worth about €221.6 million, funded from EYATH's own and European funds and including 200,000 smart household meters. Named priorities include Phase A2 of the water treatment plant, completion of the sewerage network in Western Thessaloniki and repair of the Aravissos aqueduct. Implementation is drawing down cash, though the company operates with zero bank debt.

Sustainability & Resilience

Energy is central to EYATH's climate agenda. Total market-based emissions have fallen 47.21% from the base year, against a target of a 50% reduction by 2030. Unbundled energy attribute certificates now cover most market-based emissions from purchased electricity. For supply security, EYATH has stated that its main river source and the water table were at normal levels, and that supply would be fully covered through 2030 even in worst-case drought or infrastructure scenarios.

Key Challenges

1. Reducing non-revenue water from 26.84% in 2025 towards halving it by 2030.
2. Delivering about €221.6 million of planned 2025–2029 investment under tariffs fixed for the period.
3. Containing energy costs after electricity costs rose 78.72% in 2022 and EBITDA fell sharply.
4. Expanding treatment capacity through Phase A2 of the Thessaloniki Water Treatment Plant.
5. Managing overflow and flood risk on the combined sewer network.

Major Projects