Sodium, dissolved

Overview

Sodium is a cation that is present in nearly all natural waters, although concentrations vary. Sodium is present in nearly all rocks and soils present and is frequently a cation in natural waters. One of the more common sources of sodium in water is from the dissolution of clay and felspar minerals. Sodium concentrations of more than 30-60 milligrams per liter can impart an objectionable taste to the water. Individuals on restricted sodium diets generally should maintain drinking water intake concentrations of 20 milligrams per liter or less. Information of the sodium of water is used by water treatment managers to determine amounts of chemical to add during the treatment process.

Water-quality standards and criteria are developed by the States, approved by the U.S. Environmental Protection Agency (USEPA), and then promulgated (passed into law) as standards by each State. Graphs on this website allow comparison of measured and computed data to these standards and criteria by plotting them as straight lines. When evaluating data to decide whether water quality is suitable for the intended use, viewers are cautioned to consider the uncertainty associated with these computed data.