# Rainwater Harvesting in Costa Rica: Tanks, ASADAS and Safe Water > In Costa Rica, rainwater harvesting works best as a backup for non-drinking uses like irrigation and cleaning, sized to your roof, rainfall and dry season. Most rural water comes from community associations called ASADAS, and in September 2026 32 of them reported rationing across 74 communities during El Niño. Drinking rainwater or reusing greywater safely takes proper treatment, testing and, for wastewater, compliance with national rules. Source: https://pura-verde.com/rainwater-harvesting-clean-water-costa-rica/ Last checked: 2026-10-30 Best for: homeowners, farms, lodges and travelers who want to understand water supply and conservation in Costa Rica. Who supplies water: AyA, municipalities and, in many rural areas, community water associations called ASADAS. 2026 drought: in September 2026 Conaflu reported 32 ASADAS rationing water in 74 communities, mainly in Guanacaste, Puntarenas and Alajuela. Wastewater rule: the national regulation on wastewater discharge and reuse is Decree 33601-MINAE-S (2007). Wells and springs: concessions and drilling permits are handled by MINAE's Water Directorate (Dirección de Agua). Visit: the Guanacaste Water Center in Paraíso offers tours, workshops and a native-tree nursery. *It can rain hard enough to overflow the gutters in minutes, and a few months later the same town can be rationing tap water. That isn't a contradiction. It's the difference between rainfall, the springs and wells a community depends on, the pipes and tanks that move water, and the people who manage them.* For a Costa Rican family, a restaurant, a farm or a lodge, water security is a daily practical question, not just an environmental one. A well-designed rainwater tank can cover garden and cleaning needs. A working community aqueduct keeps households supplied. A protected watershed helps springs keep flowing through the dry season. These ideas connect, but they aren't interchangeable. This guide explains how each one works, where the rules come in, and how visitors and residents can be good water neighbors. It isn't engineering or legal advice; for a real system, work with a qualified professional and the relevant authority. ## Who supplies water in Costa Rica Depending on where you are, your tap water comes from the national water utility **AyA**, a municipality or a **community water association**, known as an **ASADA**. ASADAS are especially common in rural areas and small towns. They're run by local boards, often with volunteer members, and they handle everything from protecting the spring or well to billing, repairs and water-quality testing, under AyA oversight. That's a lot to ask of a small organization. In August 2026, Costa Rica's Comptroller General [reported on an audit of 42 ASADAS](https://observador.cr/78-000-personas-estan-en-riesgo-por-fallas-en-calidad-y-disponibilidad-de-agua-en-asadas-alerta-contraloria/). It found that 32 hadn't carried out the required physical-chemical and microbiological tests in 2025, that more than half didn't know whether they had enough water for their population or where their sources are recharged, and that AyA had left most of the associations' 2025 requests for technical advice unanswered. The Comptroller said those gaps put water access for more than 78,000 people at risk. None of this means tap water is unsafe everywhere. It means quality varies by provider, and the people running small systems often need more support than they get. ## The 2026 drought: hours of water, not days In September 2026, as El Niño intensified, the national confederation of community water systems, **Conaflu**, reported that 32 ASADAS were rationing water or seeing service problems in 74 communities, affecting about 6,525 connections. [Delfino.cr's report](https://www.delfino.cr/2026/09/acueductos-comunales-reportan-racionamientos-de-agua-en-74-comunidades-por-efectos-asociados-a-el-nino) listed cantons in Guanacaste, Puntarenas and Alajuela, including Nicoya, Santa Cruz, Hojancha, Nandayure, Cañas, Tilarán, Orotina and San Ramón. Pura Green News covered the story in [Seventy-four communities ration water](/news/water-rationing-74-communities/). **Jeffry Pérez Hernández**, vice president of the **ASADA Moracia de Nicoya**, told Delfino that the community's deep wells had lost much of their flow and one had dried up completely. Some residents were getting only 3 to 4 hours of drinking water a day, and the association had asked for help getting containers so families could store water. **Emel Rodríguez Paniagua**, vice president of Conaflu, put it simply: "Hay que prepararse para la sequía," or "We have to prepare for drought." He called for coordination among the central government, municipalities, water federations, businesses and users. Those figures describe September 2026. The National Meteorological Institute's outlook cited in the same report said El Niño could last until January 2027. Conditions change week to week, so check with the local ASADA or municipality for the current situation. ## What makes a community water system work A study of seven ASADAS in the Osa Peninsula, presented as a [poster for the CONAMA 2026 congress](https://www.conama.org/comunicaciones-2026/que-sostiene-la-gestion-comunitaria-del-agua-el-caso-de-osa-costa-rica/) by researchers from Spain's Universidad Politécnica de Madrid, found a familiar set of challenges: outdated tariffs that can't fund improvements, limited planning, uneven infrastructure, uneven protection and monitoring of springs, and low participation by women and young people in decisions. The authors propose strategies around governance, tariff review, spring protection, system adaptation, inclusive training and alliances between associations. If you live in Costa Rica, the most useful questions to ask your water provider are practical ones. Who knows how to repair the pumps? Is the spring or well area protected? How often is the water tested, and are the results public? What's the plan for the next dry season? And how can neighbors help? ## How rainwater harvesting works A rooftop rainwater system has a few basic parts: - **Catchment:** the roof. Its material and condition affect water quality. - **Gutters and screens:** to keep out leaves, insects and debris. - **First-flush diverter:** sends the dirtiest first water from each rain to waste. - **Storage:** a covered, opaque tank that keeps out light, mosquitoes and animals. - **Overflow:** a safe path for excess water so it doesn't erode the ground or flood a neighbor. - **Distribution:** a pump or gravity line to where the water is used. **Sizing is about the dry season, not the wet one.** The right tank depends on roof area, how rainfall is spread through the year, how much water you'll use and how long dry spells last. On the dry Pacific side, months can pass with little rain. A tank that overflows every afternoon in October may run empty by March. A good designer calculates supply and demand instead of recommending a standard tank to everyone. **Best uses:** garden irrigation, washing vehicles and tools, toilet flushing where plumbing allows, and cleaning. These uses take pressure off drinking water supplies in dry months. **Keep it clean:** clean gutters before the rains, check screens, empty and scrub tanks on a schedule, and keep lids tight. Standing water breeds mosquitoes, which matters in a country with dengue. ## Is rainwater safe to drink? Not automatically. Clear water can still carry bacteria, parasites or contaminants from the roof. Drinking rainwater needs proper filtration, disinfection, regular testing and maintenance, and you should check what rules apply to your situation. Storage matters even for tap water. During the 2026 rationing, the **Colegio de Químicos de Costa Rica** [warned](https://www.teletica.com/amp/nacional/colegio-de-quimicos-alerta-sobre-riesgos-de-almacenar-agua-ante-racionamientos_417911) that using containers not meant for drinking water, or water of unknown quality, can lead to contamination. Its advice: use only clean, covered containers made for storing drinking water, watch for changes in color, smell or taste, and report problems to the authorities or your local ASADA. ## Greywater, blackwater and wastewater rules **Greywater** usually means used water from sinks, showers and laundry. **Blackwater** includes toilet waste. Both can carry pathogens, soaps, fats and salts, so neither is safe for casual reuse. Greywater irrigation can make sense with the right treatment and design, but it isn't a free-for-all. Costa Rica's main rule on this is the **Regulation on Wastewater Discharge and Reuse**, [Decree 33601-MINAE-S](https://ampeid.org/documents/costa-rica/decree-no-33601-minae-s-─-regulations-for-the-discharge-and-reuse-of-wastewater/), published in March 2007 and issued by the environment and health ministries. Any project that treats or reuses wastewater, especially a hotel or restaurant, should be designed by a qualified professional who works to the current regulations and permits. Why it matters: Pura Green News has reported on [wastewater problems in Corcovado National Park](/news/corcovado-sewage-red-alert/) that raised a conservation alarm, and on how [Sirena Station restored visitor access after repairs](/news/sirena-station-capacity-restored/). Poorly managed wastewater ends up in rivers, mangroves and the sea. Companies that design wastewater treatment systems in Costa Rica include **[Saxum Agua](https://gruposaxum.com/)**, the water unit of Grupo Saxum, which says it designs, builds, operates and maintains systems for hotels, industry and commerce from its base in San Pedro, San José, and **[DDi Expertos en Agua](https://www.grupoddi.com/)**, which says it has provided wastewater treatment solutions across Central America since 2006. These are examples, not endorsements. Ask any supplier for: - the effluent standard the system is designed to meet; - treatment capacity and energy use; - where treated water or sludge goes; - who operates and maintains it, and how staff are trained; - references from clients whose systems have run for years. ## Wells and springs: get the permits first Drilling a well or taking water from a spring or stream isn't a private decision in Costa Rica. Concessions for groundwater and surface water, and permits to drill, are handled by [MINAE's Water Directorate (Dirección de Agua)](https://da.go.cr/). Before you drill, find out who else depends on the same aquifer or spring. In dry regions, one new private well can affect a whole community's supply. Pura Green News has covered a [court order to protect the Tempisque River](/news/tempisque-river-court-order/), a reminder that water in Guanacaste is shared and contested. ## Upstream: the Guanacaste Water Center Protecting the land around springs and rivers can matter as much as any tank. Erosion, cattle in streams, agrochemical runoff, road drainage and deforestation all affect how much water there is and how clean it is. Dry-season fires don't help either, as our story on [Guanacaste's 2026 forest fires](/news/guanacaste-forest-fires-2026/) showed. The [Guanacaste Water Center](https://www.guanacastewatercenter.org/pages/guanacaste-water-center-1), in Paraíso, Guanacaste, is run by the nonprofit **Nandamojo Association** and focuses on land use and water stewardship in the Nandamojo watershed. It says it offers water-stewardship education for all ages, helps families adopt practices that return more water to the ground, promotes rainwater capture and supports fire-prevention networks. Its **Bees for Trees** program offers beekeeping support to families who reforest 10% of their farm. The center lists tours, workshops, school field trips and a native tree and plant nursery for visitors; contact it to arrange a visit. Its listed team includes an executive director, an association director and technical advisor **Tom Peifer**. Planting trees doesn't automatically mean more drinking water. Results depend on soil, species, land use, rainfall and groundwater. That's why demonstration sites like this, where you can see a technique and talk about whether it fits your land, are worth more than slogans. Our [reforestation guide](/reforestation-costa-rica/) and [climate resilience guide](/climate-resilience-costa-rica/) go deeper. ## Being a water-smart guest or business **For travelers:** - Take short showers, especially in Guanacaste and the Nicoya Peninsula in the dry season. - Reuse towels and sheets. - Report leaks to the front desk right away. - Ask your host where the water comes from. If it's an ASADA in a dry area, conservation matters even more. - Refill a bottle instead of buying plastic, and ask your host whether the tap water is safe to drink there. **For lodges, restaurants and farms:** - Meter your use and check for leaks regularly. - Choose plants suited to the dry season and water them early or late. - Capture rainwater for irrigation and cleaning. - Cut unnecessary laundry. - Talk with your local ASADA about how you can support the source, and follow any restrictions that apply to households. Our guides to [sustainable hotels and eco-lodges](/sustainable-hotels-eco-lodges-costa-rica/), [green building](/green-building-costa-rica/) and [ecovillages](/ecovillages-costa-rica/) show how water fits into a whole property. You can find places to stay that take this seriously on the [Pura-Verde map](/#stay). ## Frequently asked questions ### Is it legal to collect rainwater in Costa Rica? Collecting rain from your own roof for household use is common in Costa Rica. Wells, springs and streams are different: those need concessions or drilling permits from MINAE's Water Directorate. Treating or reusing wastewater falls under Decree 33601-MINAE-S. ### Can you drink rainwater in Costa Rica? Only after proper treatment. Rainwater can pick up bacteria and contaminants from roofs and tanks, so drinking it requires filtration, disinfection, regular testing and good maintenance. Many people use rainwater for irrigation and cleaning instead. ### What is an ASADA in Costa Rica? An ASADA is a community association that runs a local water system, from protecting the source to billing and repairs, under AyA oversight. They're common in rural areas and are run by local boards, often with volunteers. ### Is there water rationing in Costa Rica in 2026? In September 2026, Conaflu reported 32 community water systems rationing or seeing service problems in 74 communities, mainly in Guanacaste, Puntarenas and Alajuela, as El Niño intensified. Conditions change, so check with the local ASADA or municipality. ### How big should a rainwater tank be? It depends on roof area, how much water you'll use and how long the dry season lasts where you are. Size the tank for the dry months, not the rainy ones, and have a designer calculate supply and demand for your site. ### Can greywater be reused for irrigation in Costa Rica? It can be, with the right treatment and design, but greywater can carry pathogens, soaps and fats. Wastewater reuse is covered by Decree 33601-MINAE-S, so work with a qualified professional and follow current permits.