By Dr. Alex Tan
Updated Mar 24, 2022
NA/AbleStock.com/Getty Images
The electrical conductivity of water is governed by the concentration of dissolved ions, which are often quantified in parts per million (ppm). Because ion concentration directly drives conductivity, higher ppm values translate to higher conductivity. Industries such as water bottling and wastewater treatment—Lenntech, for example—use conductivity as a proxy for water purity.
Divide the ppm value by 0.64 to obtain conductivity in µS/m. Lenntech cites this as an average conversion, recognizing that individual ion species have distinct conductivities.
The result is expressed in microSiemens per meter (µS/m). To convert to Siemens per meter (S/m), divide by 1 000 000.
Express the conductivity in scientific notation for clarity, moving the decimal so that only one non‑zero digit precedes the decimal point and noting the exponent.
