Brunei River has a catchment area of approximately 360 sq.km. Within this area, more than 75,000 people reside. The Brunei River Estuary, which drains into Brunei Bay, is utilized for transportation, small-scale commercial fishing, recreation and waste disposal. The estuary receives major portions of the capital city's stormwater runoff along with treated and untreated sewage. It is treated like a "sink" to assimilate all nature and human-related solids, liquids and gases without regard for the risks to its ecosystem. A 1987 study concluded that the existing level of sewage discharged into the river did not have any apparent effect on its ecosystem. However, the amount of household litter and other refuse from Kampong Ayer and other small villages (Kampong) scattered along the estuary and its tributaries has reduced the aesthetic value of the estuary. The high level of bacteriological contamination near Kampong Ayer and Pintu Malim Sewage Outfall could also create a health hazard if it is not controlled. Findings indicated the river's water quality and suspended solids. Other parameters did not show significant changes because of the dilution and self-purification capacity of the river.