Indonesia is a tropical area with high rainfall, the area on land is connected by around 472 large and small rivers that flow into the sea. The estuary area is the meeting area of ​​rivers or fresh water streams with the ocean. Transportation of organic matter, minerals and sediments from upstream to the estuary and from the sea containing minerals, hence estuarine waters are more fertile than other areas. In addition, estuary areas are important habitats for several types of marine and freshwater organisms to fulfill their life cycles, which are used as spawning, foraging, and nursery grounds. This study aimed to determine the total organic contents, total Nitrogen, and Phosphorus in the estuary waters of Maros as a source of brackish water for fish pond aquaculture in Maros Regency. The research was conducted in the estuary waters of Maros for three months from September to November 2020. Sampling was conducted four times with an interval of once every 15 days. Sampling was carried out at five stations based on water movements to the estuary, station A was located at the seawater, station B was located in the pond wastewater locations, station C was water sources from residential waste, station D was located in the river, and station E was the estuarine water. The results showed that the dominant water quality parameters affecting estuarine water quality were salinity, total organic matter, nitrogen content, either in the form of ammonia, nitrate, or nitrite, and phosphorus content, especially phosphate. Water entering the estuary has an impact on high concentrations of total organic matter, increased concentrations of Total N, and phosphorus. The results of water quality analysis in estuaries showed that salinity, organic matter, ammonia, nitrite and nitrate, and phosphate exceed the standard threshold for water quality standards for fish pond aquaculture. Thus, the waters of the Maros estuary are not suitable for aquaculture, especially for the 5 observed stations (A, B, C, D and E).