Buying land in Costa Rica: water and wastewater checks before you sign

Many people fall in love with a lot in Costa Rica from the view: the ocean below Ojochal, the sunset over Tamarindo bay, the green hills of Atenas. Then, months later, they learn the lot has no water connection, or that the soil cannot take a drain field, or that the only flat spot for the septic system is exactly where they wanted the pool.

Those surprises are avoidable. Water and wastewater are among the first things a municipality checks before it issues a building permit, so they should be among the first things you check before you buy. This guide lists the questions and documents that matter, in plain English. It is general information; your lawyer handles the title, and an engineer should look at the site itself.

Why water and wastewater come first

To get a building permit, a house has to show two things: where its drinking water comes from and where its wastewater goes. Most beach towns have no public sewer, so the lot itself must treat and absorb the water from the septic system. If either answer is "nowhere", the lot is not buildable as you imagined it, no matter how good the view is. Our guide on permits for building a house shows where these documents fit in the full process.

Check 1: the water availability letter

The key document is the water availability letter (carta or constancia de disponibilidad de agua). It is issued by the operator that provides water at that exact point:

• AyA, the Costa Rican Institute of Aqueducts and Sewers, in much of the country;
• an ASADA, a community-run water association, in many rural and coastal towns;
• the municipality, in some cantons.

The operator checks that there is a pipe in front of the property and enough water to serve it. A missing pipe or a stretched supply are common reasons for a negative or conditional answer, especially in fast-growing coastal areas during the dry season.

What to do as a buyer:

1. Ask the seller who supplies water to the area, and confirm it with neighbors.
2. Ask the seller for a recent availability letter, or make the purchase conditional on getting one.
3. Read the letter carefully: it may be positive, negative, or conditioned on works such as a new pipeline that the owner must pay for.

For larger developments the requirements are stricter. The CFIA's public requirements site, Trámites Construcción, lists what each type of project must present. Our water systems service covers the technical side.

Check 2: if there is no public water

A negative letter is not always the end, but it changes the budget and the timeline.

A well for domestic use. The Water Law (Law 276) allows wells inside your property for domestic use, keeping distances from neighbors' wells and sources. A hand-dug well for domestic use is registered with MINAE's Water Directorate.

A drilled well. Drilling is regulated by Decree 43053-MINAE. Every drilling permit is granted for exploration, together with a concession request filed through SIPECO, the Water Directorate's online system. Only companies registered with the Water Directorate may drill, working with a responsible geologist. After drilling come the final report and a pumping test, and only then does the Directorate decide whether the well can be used. Near the coast, it can require monitoring for saltwater intrusion and limit extraction. Details are in our guide on water well permits.

A spring or creek. Taking water from a surface source for anything other than the uses the law allows without a permit requires a water concession from the Water Directorate.

Two practical points: a well is not instant, and the drinking water source must be planned together with the septic system, because the regulation sets distances between them.

Check 3: can the lot treat its wastewater?

Decree 42075-S-MINAE decides whether a lot can use a septic tank and drain field. Before buying, check these conditions with an engineer:

• Slope. Infiltration trenches are not allowed on slopes over 30 %. On steep lots there may still be a flatter area that works, but it has to be found and measured.
• Water table. It must be at least 1.5 m below the bottom of the trenches. Flat land near estuaries, mangroves or rivers often fails this rule in the rainy season.
• Soil. The percolation test must give a rate between 2 and 24 minutes per centimeter. Too fast or too slow, and trenches are not allowed.
• Space. The field needs private green area, never under driveways, parking, decks or pavers, and its size grows on slow soils. See how a septic system is sized.
• Setbacks. At least 1 m from property lines and buildings, 1.5 m from drinking-water pipes, 2 m from slopes steeper than 25 %, 3 m from water tanks, and the protection areas around springs, rivers and streams that the Water Law and the Forestry Law establish.

The single most useful check is a percolation test before closing. It usually spans two days on site, because the holes must stay full of clean water for at least 24 hours before measuring. It tells you whether a drain field is possible and roughly how large it must be. Our percolation test service explains what we do.

If the lot fails, the alternatives are a treatment plant that discharges with a permit or reuses its water, or a sewer connection where one exists. Those are possible, but they belong in the price negotiation, not in a surprise after closing.

Check 4: the maritime zone and other special areas

Beachfront land has its own rules. Under Law 6043, the maritime zone is the 200-meter strip measured from the ordinary high-tide line. The first 50 meters are public. The other 150 meters are a restricted zone, granted by the municipality as a concession, not as titled property. Anything built there, including the septic system, follows the concession and the local coastal zoning plan.

Inland, check whether the lot touches a river, a creek, a spring or a protected area. The protection strips reduce the usable land, and the drain field must stay outside them.

Check 5: what is already on the lot

Look for old structures: a cabin with a cesspit, a pipe running to a creek, an old well. Decree 42075 bans absorption pits for any wastewater and gave owners in areas with piped water five years from 2020 to replace latrines and cesspits. An existing problem becomes yours on the day you sign. If the property already has a house, use our guide on buying property with a septic system.

A short checklist

Before you sign, try to have:

• the registered survey plan and the municipal land use certificate;
• a water availability letter from the right operator, or a clear plan for a well;
• a percolation test report and a site walk with an engineer;
• the slope and the approximate water table where the drain field would go;
• confirmation of whether the lot lies in the maritime zone or near protected areas.

Ingeniería de las Aguas, based in Palmares, Alajuela, reviews lots for wastewater feasibility, designs septic systems and drain fields from the percolation test results, designs treatment plants, and handles wastewater permits with the Ministry of Health, MINAE, SETENA, AyA and municipalities. We work in Guanacaste, the Central and South Pacific, the Central Valley and Limón. If you are about to buy, send us the lot location and the survey plan on WhatsApp or through our contact page, and we will tell you which checks make sense for that site.