The majority of Tutuila population resides near the base of the mountains and adjacent to the sea. Villages are numerous and widespread, with houses, piggeries and plantations reaching up into the hills to take advantage of what little workable and productive land is available. Previously, villages relied on streams for household and drinking water, collected from reservoirs on the stream above the village. These reservoirs still exist, and some villagers use this water to supply piggeries, for washing or for outdoor showers.

However, a rapidly growing population has negatively impacted many village streams, and human and agricultural wastes are directly and indirectly discharged into waterways. Consequently, stream water in heavily developed areas has become polluted by elevated bacterial levels and is unsafe for drinking or swimming. Many streams and their surrounding watersheds are continuously altered by unchecked development. For example, houses are build in close proximity to streams or, alternatively, stream flow is obstructed by refuse, building materials and other waste materials, which results in unnecessary destruction and flooding when flow is high. Agricultural development, such as the removal of large numbers of trees for plantations, and construction projects, further contribute to soil erosion and sedimentation of freshwater and marine environments. This is especially apparent after heavy rains and flooding. Sedimentation and coastal pollution are both known to contribute to coral reef degradation.

The majority of the population is supplied with safe, chlorinated drinking water. Pumped from a limited and deteriorating ground water source, most of which comes from the Tafuna Plains. This plain is the only large, flat area of land on the island, but it is also the most densely populated.

Combined with a rapidly growing population, environmental problems such as the limited supply of drinking water, pollution, waste disposal, coastal and stream alteration, and soil erosion are serious environmental issues in American Samoa.

View PDF of American Samoa: Environmental trends in 2004, by Peter Craig.