The engineers design for a sewage treatment plant is under way. A strong submittal is a foreign supplied plant that features virtually no discharge of dirty water. It reuses the treated brown water to irrigate the plants and grass. This sewage system is used widely in Central and South America and is the preferred system of the Nicaraguan environmental authority. Engineering details are being worked around this system. Tamarindo will have a well designed, complete waste water treatment facility.

In the unlikely case that a sewage plant is not approved, we will consider septic. There are two basic types of septic systems. The system that most people know is the older style with the "lateral lines". In this type of system, the affluent is broken down "anaerobically", or without oxygen. There is usually no mechanical device attached to these system whatsoever unless a lift pump is needed. Over time, the affluent breaks down and migrates into the lateral lines where it leaches out into the soil. You can often see these lateral lines in the dry summertime as bright green streaks.

The second type of system is the newest technology. These are called "aerobic" systems. These are actually mini-wastewater treatment plants not unlike the huge plants that might serve a city. In this system, the matter is broken down in two different tanks. The first tank is the settling tank just like the tank on the older style systems. The material is broken down without oxygen and then moves from the first tank to the second tank. The second tanks has a pvc line run into the bottom which is attached to an air compressor at the surface. The air compressor is constantly forcing oxygen into the tank, thus breaking down the matter "aerobically" or "with oxygen". There is also a third tank, which is simply a holding tank. When the third tank reaches a certain height, a sprinkler pump within the tank pumps the water out to the sprinkler lines. Between the second and third tank is a pipe which can be easily accessed from the surface. About once a month, chlorine tablets are dropped into this pipe. The treated water slowly washes by the chlorine tablets and is chemically sanitized.

Both types of septic systems should be pumped approximately once every three years. This will cost about $300.