Escazú and Santa Ana, on the west side of San José, are where many foreign families, executives and retirees choose to live in the Central Valley. The housing is varied: gated condominiums, townhouse developments, hillside homes in the Escazú mountains, older houses on large lots, and new towers and mixed-use buildings along the main roads. Each canton has its own municipality, Escazú and Santa Ana, which handles construction permits.
Unlike the beach towns, this is an urban area. Some streets have a sanitary sewer; many properties, especially condos, hillside homes and newer developments, treat their own wastewater. Knowing which case you are in is the first step.
Sewer or your own system?
Before designing anything, find out whether a sanitary sewer runs in front of the property and whether its operator, usually AyA (Costa Rica's national water and sewer utility), accepts the connection. If it does, the project may avoid a full treatment plant, although wastewater sent to a sewer still has to meet the limits for sewer discharge in Decree 33601-MINAE-S, and non-domestic wastewater may need pretreatment.
If there is no sewer, the property needs one of two solutions:
- a septic system (septic tank plus drain field) for homes and small buildings using up to 190 cubic meters of drinking water a month, under Decree 42075-S-MINAE;
- a treatment plant approved under Decree 39887-S-MINAE for anything larger, such as condos, office buildings and commercial centers.
Condos: plants with paperwork
Many gated condominiums in Escazú and Santa Ana have their own treatment plant, built when the project was developed. Years later, the residents' association (often called the HOA by foreign owners) is responsible for it, and the duties are real:
- routine measurements of flow, pH, settleable solids and temperature;
- lab analyses every six months for flows up to 100 cubic meters per day, or every three months above that;
- operational reports to the Ministry of Health on the same schedule, within 10 business days after each period, prepared in the Ministry's SIRROAR online system;
- a logbook of operation, maintenance, incidents and sludge removal.
Our page on HOA wastewater plant compliance explains each one in plain English.
Common problems we see in older condo plants here: more units or more residents than the design assumed, equipment that has been patched instead of replaced, odors that bother neighbors in a dense area, and lab results that fail intermittently. An engineering review usually tells you whether you need better operation, a partial upgrade or rehabilitation, or an expansion. If you are buying into a condo, read our checklist for buying a condo with a treatment plant.
Hillside homes in Escazú
The upper parts of Escazú are steep. For a house with a septic system, Decree 42075 does not allow drain field trenches on slopes steeper than 30 %, and asks for a 2-meter setback from the top of slopes steeper than 25 %. The regulation also sets a higher design flow for the metropolitan area: 300 liters of wastewater per person per day, compared with 240 in other urban areas. On a steep lot with a large house, those two facts together can make the drain field the hardest part of the project. Sometimes the answer is to pump treated water to a better part of the lot with a small pumping station, or to choose a compact treatment unit.
For houses that already have a septic system and give trouble, start with septic smells and overflows. For new homes, an improved septic tank with a drain field designed from a percolation test is the usual starting point.
Stormwater: the urban issue
Every new roof and driveway sends more rain, faster, into streets and creeks. Municipalities in the metropolitan area review where projects discharge their stormwater, and creeks that cross Escazú and Santa Ana respond quickly to heavy afternoon storms in the rainy season. A proper stormwater drainage design protects your neighbors and also your own wastewater system: rainwater that gets into a septic tank or plant dilutes the treatment and can flood the drain field.
How we help in Escazú and Santa Ana
Ingeniería de las Aguas, based in Palmares, Alajuela, works throughout the Greater Metropolitan Area. We:
- review, optimize, upgrade and rehabilitate condo and commercial treatment plants;
- design and build new plants, sanitary sewers, pumping stations and stormwater drainage;
- design and build improved septic systems and drain fields from the percolation test results;
- prepare operational analyses and reports and follow up on system performance;
- handle permits with the Ministry of Health, MINAE, SETENA, AyA and the municipalities of Escazú and Santa Ana, and supervise construction.
Looking for a quieter place further west? See Atenas and Grecia.
Send us the location, the type of property and, for condos, the latest operational report, on WhatsApp, or use our contact page.