The river nearest San Salvador is the ''Acelhuate'', which is  long. Although not within the municipality, it forms a natural boundary between San Salvador and Soyapango. The ''Acelhuate'' served as a water source for San Salvador during the late 1800s and early 1900s, but due to urbanization is now polluted. There are small streams running down from Lake Ilopango, and a few old aqueduct systems, but the municipality itself has no major bodies of water.