The endless issue: water pollution

Mira writes*

Costa Rica is proud of its sustainability, but it’s mismanaging its water. As the head of the Institute of Aqueducts and Sewers (AyA) said in 2019:  “We sell ourselves as a green country, but in terms of wastewater and the quality of our rivers we have not been consistent”. In the country, low water quality, and subsequently high levels of pollution has negatively impacted the lives of many.

Specifically in urban areas, this water pollution can directly be seen in rivers. According to La Nacion, San Jose’s levels of water pollution are continuously increasing as untreated wastewater is diverted into rivers rather than into sanitary sewer systems. Rivers also suffer from trash dumping. In a further article the minister of health commented on the threat this posed to a “potential harmful disease outbreak”. In a 2013 research paper on “water supply and sanitation,” Bower found linked high levels of water pollution to untreated urban and rural wastewater. Pollution was worse near hospitals. The release of chemicals, antibiotics etc. into the water supply threatens ecosystems and people.

A 2021 study of water quality in Cartago (an agricultural region close to San Jose) found high levels of pollutants and chemicals in the water. Pollution was linked to urban population, erosion and agriculture — specifically from unauthorized pesticides.

Overall the agricultural sector is a large contributor to water pollution. Agriculture affects water quality through fertilizers, which in recent years have only increased in concentration. Simultaneously, contamination through organic matter from livestock farming. Both integrating into the water system as ground water, run off water and through irrigation.

What is being done? Agua Tica is promoting [pdf] good agricultural practices (GAPs). In the past much produce has been grown with the help of agrochemicals and other synthetic fertilizers, with the intention of increasing crop yields. Agua Tica trains farmers on implementing sustainable farming practices at a low cost. Many farmers have implemented GAPs as they wanted to protect their environment and people from pesticides.

The Los Tajos wastewater-treatment plant, opened in 2015, has increased wastewater treatment capacity. The AyA is working to expand and repair sewer infrastructure around the capitol.

Bottom Line: Costa Rica’s poor management of water has led to high water pollution mainly caused by the urban population, agriculture and industry. To resolve this crisis farmers are being trained and the sewage system is being expanded.

* Please help my Water Scarcity students by commenting on unclear analysis, alternative perspectives, better data sources, or maybe just saying something nice 🙂

Author: David Zetland

I'm a political-economist from California who now lives in Amsterdam.

2 thoughts on “The endless issue: water pollution”

  1. Hello Mira,
    I found your blog post very interesting. I was surprised to learn that despite being so engaged in sustainability, Costa Rica has such water pollution issues. You highlighted well the threats it causes to human health. I think that it could be useful to add some precise data about how many lives were/are impacted by this pollution. The explanation of the main cause of this pollution, agriculture, was clear and detailed. I think that a point to look at more for your case study is how farmers accepted and implemented GAPs. I also wonder if anything was done to cope with trash dumping in the rivers. Overall your blog post was insightful and I really appreciated reading it!

  2. Hey Mira!

    I enjoyed reading your post, so I did a quick search about Costa Rica’s pesticide use. I saw two news from 2015 saying that the country was the most “voracious” consumer of pesticides in the world (e.g., In addition, a more recent one from 2022 stated that the country “uses up to 8 times more pesticides than other OECD countries in America” (,%2C%20M%C3%A9xico%2C%20Chile%20y%20Colombia.).

    With this in mind, I wonder how pesticide companies react to the measures being taken to improve Costa Rica’s water quality, as it necessarily cripples their profits. Do they work as lobbyists, and is it effective? How do they affect the way in which the government goes on about water? On the whole, it is interesting to think about the conflict of interest of improving water quality while trying to maintain the productivity of crops and keeping big investors “happy”.

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