Costa Rica’s national water utility is under renewed scrutiny after officials warned that more than half of the water produced by the Instituto Costarricense de Acueductos y Alcantarillados (AyA), in the Greater Metropolitan Area failed to become billed consumption between 2019 and 2023.
AyA’s unaccounted-for water rate in the GAM remained between 53% and 58% during that period. The rate was 53% in 2019, reached 58% in 2022 and closed at 56% in 2023, meaning that between 53 and 58 of every 100 liters produced in the metropolitan system did not generate billed revenue. The situation has been described as a structural problem for AyA’s finances and for the delivery of potable water service.
Unaccounted-for water includes water lost through leaks, pipe failures and other physical losses, but it also includes commercial losses such as meter problems, irregular connections and water that is used but not billed. Even when that water is not charged to customers, AyA still pays to capture, treat, pump and distribute it.
The warning adds to findings that a 2023 tariff adjustment would not recognize 10% of AyA’s unaccounted-for water in 2024, creating projected losses of ₡28.384 billion. Auditors also found that, in 2023, more than half of the water produced by AyA was not counted or billed.
The findings painted a wider picture of strain in the public water system. AyA’s potable water coverage fell from 99.7% in 2021 to 95.6% in 2023, leaving an estimated 94,267 people in AyA service areas without potable water that year. Rejected water service requests also rose sharply, from the equivalent of 102,759 people in 2022 to 564,642 people in 2023, mainly because of reduced available water and lack of infrastructure.
The problem is not only the volume of water lost, but also AyA’s limited ability to measure where it is going. Nearly half of water use points lacked micrometers in good condition, while most AyA water systems had no information to determine how well leaks were being managed.
The main public project meant to attack the problem is RANC-EE, the Reduction of Unaccounted-For Water and Energy Efficiency project. The project has been under execution since 2019 with an investment of $179 million, but had reached only 14% financial progress as of August 2024. One of its key goals is reducing unaccounted-for water in the Greater Metropolitan Area and seven priority regional systems.
The project includes pipe replacement, pressure management, leak detection, meter upgrades and operational changes. Previous planning called for replacing hundreds of kilometers of pipe, improving pressure management and carrying out proactive leak repairs.
AyA has said recent actions have improved the share of water it can bill by four percentage points. The institution says it has replaced more than 480,000 household meters, renewed 392 kilometers of pipe and installed smart devices as part of pressure-management work in the GAM, measures it says have optimized the use of more than 13 million liters of water per day.
AyA President Lourdes Suárez has framed the latest findings as part of a problem inherited from earlier administrations. She said AyA began a reorganization process in 2022 and consolidated an institutional project portfolio in 2024, one of the weaknesses noted by oversight officials.
The pressure is likely to grow as water demand rises in urban, coastal and tourism-heavy areas. Costa Rica is also heading into a period of climate risk, with El Niño expected to bring less rainfall and higher temperatures to several regions during the second half of 2026. Reduced rainfall could place more pressure on communities already facing water supply problems.
For AyA, the issue is now both financial and physical. Every liter lost through old pipes, broken meters or illegal connections weakens the institution’s revenue while adding pressure to a system already struggling to expand service, guarantee continuity and keep up with demand.
