Policy · Corcovado National Park, Osa, Puntarenas

Corcovado Sewage Problems Spark a Civil-Society 'Red Alert'

On Aug. 10, 2026, the Parlamento Cívico Ambiental, a coalition of Costa Rican environmental groups, published a manifesto declaring Corcovado National Park on 'red alert' after health and water authorities confirmed untreated wastewater from Sirena Biological Station was reaching park waterways. The alert came from civil society, not the government, and it asked for an investigation, a national audit of park infrastructure and more money for SINAC.

By Pura-Verde.com Editors · Published October 30, 2026
Original report: The Tico Times: Corcovado National Park Placed on Red Alert Over Sewage and Crumbling Infrastructure (2026-08-13)

Corcovado National Park, the wild heart of the Osa Peninsula, spent much of 2026 in the news for something no visitor wants to hear about: sewage. In August, a coalition of Costa Rican environmental groups published a manifesto putting the park on "red alert." It's worth being clear about what that label means. This was a civil-society warning, not a government emergency declaration, and the park stayed open while the debate played out.

Who issued the Corcovado red alert

The alert came from the Parlamento Cívico Ambiental, an umbrella group of environmental organizations. Its manifesto, titled "For our protected areas: Corcovado on red alert," was released on Aug. 10, 2026, and pegged to the first 100 days of President Laura Fernández's government. It was signed by the group's officers: president Bernardo Aguilar González, vice president Victoria Rudín Vega, and secretaries Oscar Moya Cantero and Melanie Pérez Vargas, as delfino.cr reported on Aug. 12.

The Tico Times covered the manifesto on Aug. 13 and summed up its central argument in one line, translated as "Corcovado is not the problem: it is the alarm." In other words, the coalition sees Sirena as a symptom of how Costa Rica funds and maintains all of its protected areas.

What went wrong at Sirena Biological Station

Sirena is the ranger and research station deep inside Corcovado where most overnight visitors sleep and where many day trips by boat end up. Its small wastewater treatment plant was designed in 2017 for roughly 100 people a day, according to figures from the Environment Ministry (MINAE) cited by The Tico Times. Since 2022 it's regularly handled more than 200, and the station has gone years without a steady electricity supply to run it.

Inspections by the Ministry of Health and the national water utility, AyA, confirmed that wastewater was being released into a stream inside the park, the Quebrada Camaronal, without proper treatment or operating records. A November 2025 AyA check found the discharge failed a little more than 80% of the criteria tested, including limits on organic load and suspended solids. The Health Ministry had ordered fixes by the end of 2025, and the follow-up found the plan hadn't been carried out. Our clean water guide explains the national wastewater discharge rules that plants like Sirena's are meant to meet.

A tug-of-war over visitor numbers

The pollution reports collided with a long-running fight over how many people Corcovado can handle.

• In 2023, SINAC raised the park's daily ceiling from 560 to 700 visitors. On Aug. 8, 2025, the Constitutional Chamber ordered that change revoked because the resolution didn't show the technical basis for it, Semanario Universidad reported.
• In late June 2026, Juan José Jiménez Espinoza, then interim director of the Osa Conservation Area (ACOSA), cut Sirena to 150 people a day (100 day visitors and 50 overnight guests) because of the risk of untreated discharges.
• On July 1, Environment Minister Mónica Navarro Del Valle reassigned him to a desk post at SINAC headquarters, which set off protests on the southern Pacific coast.
• In early July his successor, Ólger Méndez Fallas, raised the limit to 225 a day through September. Semanario Universidad explained that the increase leaned on an AyA view that a separate restroom block at Los Naranjos could serve day visitors without using the broken plant.

Local guides and tourism chambers pushed back against the cuts, since guided Sirena trips are an important source of income for communities around the park.

What the coalition asked for

The manifesto made four main demands:

1. A full investigation of the Sirena discharges, with responsibilities assigned, reports and health orders made public, and immediate repairs.
2. A public national audit of the sanitary, operational and environmental infrastructure of every protected area.
3. A verifiable budget increase for SINAC, with more staff, equipment and maintenance.
4. A review of permits, concessions and commercial activity inside protected areas, with more transparency.

SINAC, for its part, said it had asked the Rural Development Institute for more than 2.63 billion colones for a full overhaul of Sirena's infrastructure and had set aside 50 million colones for immediate work. Neither delfino.cr nor The Tico Times reported a direct government reply to the manifesto itself.

What happened next

On Sept. 17, 2026, SINAC restored Sirena's daily limit to 366 people, saying the park had met the health orders and that the treatment plant had been restored, according to delfino.cr. We cover that decision in detail in Sirena Station's restored visitor access. The Tico Times noted that MINAE had also asked the Constitutional Chamber for more time to comply with the 2025 ruling, so the legal question of how many visitors Corcovado can safely take isn't settled.

For travelers, the practical takeaway is simple: Corcovado can only be visited with a licensed guide, Sirena closes every October for maintenance, and daily limits can change on short notice. If you're planning a trip, check current rules with SINAC or your guide, and browse other national parks on our map. For a look at another Osa conservation story, see the investigation into peccary hunting.

Frequently asked questions

Was Corcovado National Park officially put on red alert?

No. The "red alert" was declared by the Parlamento Cívico Ambiental, a coalition of environmental groups, in a manifesto released Aug. 10, 2026. It wasn't a government emergency, and the park stayed open.

What was the problem at Sirena Station?

Health and water authorities found that Sirena's wastewater plant, built for about 100 people a day, was releasing poorly treated water into a stream inside the park after years of overuse and unreliable power.

Is Sirena Station open to visitors now?

SINAC restored Sirena's limit to 366 people a day on Sept. 17, 2026. Sirena closes each October for maintenance and heavy rain, so confirm dates with SINAC or a licensed guide before you book.

Do you need a guide to visit Corcovado?

Yes. Entry to Corcovado requires a licensed guide and an advance reservation, and each sector has its own daily visitor limit.

Sources and original reporting

1. The Tico Times: Corcovado National Park Placed on Red Alert Over Sewage and Crumbling Infrastructure (2026-08-13)
2. delfino.cr: Organizaciones ambientales piden investigar vertidos de aguas residuales en Corcovado y auditar áreas protegidas (2026-08-12)
3. Semanario Universidad: Sinac vuelve a aumentar el aforo en Corcovado tras salida de director que alertó por colapso ambiental (2026-07-28)
4. Semanario Universidad: Sala IV ordena revocar resolución del Sinac que subía de 560 a 700 visitantes al Parque Nacional Corcovado (2025-08-12)
5. delfino.cr: Parque Nacional Corcovado restablece aforo de 366 personas diarias en Estación Biológica Sirena (2026-09-18)
6. The Tico Times: Costa Rica Restores Visitor Capacity at Corcovado's Sirena Station (2026-09-19)

We wrote this story from the published reports and official sources above. We didn't interview the people named unless the story says so.