01
About the Utility
Acea is a Rome-based multi-utility group whose businesses span water, electricity networks, environment and energy, so its consolidated results describe far more than water. Its water segment brings together the group’s integrated water operations in Italy, including GORI and Acquedotto del Fiora. The principal operator, Acea Ato 2, runs the integrated water service for Rome and surrounding municipalities in central Lazio and is 96.5% owned by the parent. Its tariffs and service quality are regulated by ARERA. The current tariff approval covers a served resident population of 3,942,215 in 105 municipalities, and the service area has widened with each regulatory determination.
02
Water System
Rome’s operator delivers drinking water through aqueducts, adduction mains and a distribution network that has lengthened each year as municipalities have joined the service. Water losses are the system’s central operating constraint: measured under ARERA’s water-balance method, they declined each year after 2018 but rose again to 40.2% in 2023. The regulator’s own percentage-loss indicator for that year recorded 42.07%, placing the operator in class D, and set a 5% annual reduction in linear losses as the objective for the next two years. Pressure management using 154 hydrovalves and about 68 km of rehabilitated mains formed part of the response, while non-conforming drinking water samples and service interruptions both fell.
Water losses
Acea Ato 2 water losses as a percentage, ARERA resolution 917/17 method, 2018 to 2023 (calendar years)
Reported actuals for ATO 2 Lazio Centrale (Rome plus municipalities acquired by each year-end). Each year uses the latest sustainability report that publishes it; earlier editions give 44.3% for 2019, 42.4% for 2020 and 39.8% for 2021. ARERA's own M1b indicator for 2023 is 42.07% on a different basis.
Sources: Acea Group sustainability reports 2020, 2021, 2022 and 2023.03
Wastewater System
Sewerage and wastewater treatment are part of the same integrated service, so collection, treatment and discharge sit with the same operator as supply. Its sewer network extends well beyond the capital, although more than 4,000 km of it lay within Rome in 2019. ARERA’s quality indicators point in different directions. Sewer flooding and spills fell to 0.77 per 100 km in 2023, but the share of wastewater samples exceeding discharge limits worsened, moving the operator into class C after class B in 2019. Sludge sent to landfill is also measured as a regulated quality outcome.
04
Investment & Priorities
Acea’s capital spending is increasingly concentrated in water. The water segment invested €890.8 million in 2025, and the company presents that spending as restarting major works, including the doubling of the Peschiera system, although its main works have yet to begin: Affaritaliani reported in July 2026 that they are due to start in 2027. Looking ahead, the five-year Business Plan provides about €4.7 billion of investment for the regulated Water Italy business and projects its regulatory asset base at €6.9 billion by 2028.
05
Sustainability & Resilience
Acea’s environmental reporting covers the whole group rather than water alone. Renewable sources met 39% of group energy consumption in 2025, up from 37% a year earlier, while indirect emissions from purchased energy fell on both location- and market-based measures and gross direct emissions edged higher. Regulation also links quality to earnings: ARERA’s incentive mechanism recognised a group premium for technical and contractual quality, although the Rome operator’s own contractual-quality result was zeroed under the scheme’s formula.
06
Key Challenges
- Reducing water losses in Acea Ato 2’s network after the 2023 reversal of an improving trend.
- Delivering a larger water investment programme, including the Peschiera doubling, on schedule.
- Improving wastewater discharge compliance as samples exceeding limits rise.
- Maintaining service quality as the regulated service area adds municipalities.