What type of water feature is typically considered to be a fresh water source?

An aquifer is typically considered a freshwater source because it is a geological formation that can store and transmit water. Aquifers are primarily composed of permeable materials such as sand, gravel, or fractured rock that allow water to flow through them. They are crucial for supplying drinking water and irrigation, as they hold substantial amounts of freshwater that can be accessed by wells.

In contrast, oceans contain saltwater, making them unsuitable as a freshwater source. Wetlands can contain both freshwater and saltwater, but they are often regions of transition and can vary significantly in water salinity. Reservoirs can store freshwater, but they are man-made structures that store surface water from rivers or rainfall. An aquifer, however, is a natural underground storage system specifically associated with freshwater, making it the correct answer in this context.