The short answer is that in most of Costa Rica you can drink the tap water, and there is a legal standard behind that rather than just a reputation. But “most” is doing real work in that sentence, and where you choose to live changes the answer more than the country does.
There is an actual standard, and it has a number
Drinking water quality is governed by Decreto Ejecutivo Nº 38924-S, the Reglamento para la Calidad del Agua Potable, published in La Gaceta on 1 September 2015 and amended by Decreto 41499-S in November 2018.
It defines potable water as treated water meeting maximum admissible values across aesthetic, organoleptic, physical, chemical, biological, microbiological and radiological criteria — and it splits the work in two. The Ministerio de Salud carries out surveillance, inspecting and issuing sanitary orders. The operators carry out day-to-day control, testing turbidity, odour, taste and free residual chlorine daily, with microbiological and chemical testing at set intervals.
So when someone says the water here is potable, there is a specific decree they are implicitly citing.
Who actually supplies your water
This is the part that decides your answer, and most people arriving have never heard of the distinction.
Four kinds of operator supply Costa Rica. On the most recent detailed national figures — from the Laboratorio Nacional de Aguas, for 2016 — the split was roughly:
- AyA, the national utility — about 47% of the population
- ASADAs, community-run rural water associations — about 30%
- Municipal systems — about 14%
- ESPH, the Heredia public services company — about 5%
The gap nobody mentions
In that same national dataset, the share of supplied water rated as potable was:
- AyA — 98.8%
- ESPH — 99.4%
- Municipal systems — 98.1%
- ASADAs — 78.1%
That is a twenty-point gap, and it affects roughly 1.4 million people, close to a third of the country.
It is worth being precise about why. ASADAs are not held to a lower legal standard — the decree names them explicitly as public operators bound by the same rules. The gap is in outcomes, not in the regulation: small community systems, often in remote areas, with less infrastructure and less laboratory capacity behind them.
Nationally, somewhere around 92 to 94 per cent of the population receives water classified as potable, depending on which official year you take. Roughly 99.5% have piped water of some kind — and those two figures are not the same thing. A statistic about access to piped water tells you nothing about whether it is drinkable.
It varies enormously by canton
The national average hides the picture. On 2021 figures, fifteen cantons were above 95% potable coverage, while Talamanca, Sarapiquí and Alvarado were below 60%.
If you are choosing where to live, that spread matters more than any national number. Two houses an hour apart can be on entirely different water realities.
What goes wrong, when it goes wrong
The system is not theoretical. The Ministerio de Salud publishes its interventions, and recent years give a fair sense of what real incidents look like.
Turrialba, February 2024. A sanitary order restricted the municipal aqueduct to handwashing and personal hygiene only — drinking and cooking were prohibited until two consecutive clean samples were obtained after the tanks were cleaned.
San José metropolitan area, January 2024. Hydrocarbons were detected in the Los Sitios–Guadalupe system, and a sanitary order was issued against AyA covering thirteen districts across five cantons. Note what that kind of contamination means in practice: boiling does not help with hydrocarbons. The instinct to boil is a microbiological instinct, and it is the wrong tool here.
Alajuelita, September 2023. A sanitary alert over suspected contamination — then testing found the water met the standard, and the alert was lifted a week later.
Vázquez de Coronado, May 2026. AyA detected hydrocarbon traces at the El Rosario intake and closed it preventively; the source was traced to a commercial premises and a closure order issued.
Read those together and the picture is reassuring in an unglamorous way: problems occur, they are detected, and they are acted on publicly. That is more than can be said in a lot of places.
The other water problem: supply, not quality
Quality and reliability are different questions, and the second one has been getting worse in the Central Valley. Service interruptions in the Greater Metropolitan Area rose from 398 cuts in 2015 to 3,184 in 2023, having peaked above 7,000 in 2020. More than half the water produced nationally is lost before it reaches a tap.
So the practical experience of water in Costa Rica is less “is it safe” and more “is it running today”. A storage tank on the property is a normal thing to have here, and worth asking about.
What to ask before you commit to a house
- Which operator supplies it? AyA, the municipality, ESPH, or an ASADA. This is the single most informative question, and any seller or landlord will know the answer.
- Is there a storage tank? In much of the Central Valley this is about interruptions rather than quality.
- What happens in the dry season? Local knowledge on this is worth more than any statistic.
- Has the area had sanitary orders? They are published, and they are specific to systems rather than to regions.
The honest summary
No Costa Rican authority declares that tap water is drinkable everywhere in the country, and you should be wary of anyone who claims otherwise. What the State publishes is a percentage — and a percentage in the low nineties necessarily means a minority who are not covered.
For most foreign residents, living in the Central Valley or a serviced coastal town on an AyA, municipal or ESPH system, the tap water is treated, tested and drinkable. In rural areas served by a community ASADA, it is worth asking rather than assuming.
Choosing where to live in Costa Rica?
Water is one of several things that vary far more by canton than by country — along with healthcare access, internet, roads and how long anything official takes.
CRIE — Costa Rica Immigration Experts handles residency applications, renewals, permanent residency and citizenship for people making the move.
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Figures are taken from the Reglamento para la Calidad del Agua Potable (Decreto 38924-S), the Laboratorio Nacional de Aguas, the Ministerio de Salud’s published sanitary orders and the Estado de la Nación. General information only — water quality is specific to the system serving a given property.
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