Conductivity

Electrical conductivity or specific conductance is a measure of a material's ability to conduct an electric current. The conductivity (or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity. The SI unit of conductivity is Siemens per meter (S/m).

Conductivity measurements are used routinely in many industrial and environmental applications as a fast, inexpensive and reliable way of measuring the ionic content in a solution. In many cases, conductivity is linked directly to the total dissolved solids (T.D.S.). High quality deionized water has a conductivity of about 5.5 micoSiemens per meter (μS/m), typical drinking water in the range of 5-50 milliSiemens per meter (mS/m), while sea water about 5 S/m (i.e., sea water's conductivity is one million times higher than deionized water).

For more, visit the Wikipedia entry for aqueous solution, URL: http://en.wikipedia.org/wiki/Conductivity_(electrolytic)