Conductivity serves as an economical, low-maintenance indicator of water quality. High-quality water with minimal contaminants exhibits low conductivity. Compared to pH measurement, conductivity requires far less maintenance and minimal calibration. Common applications include boiler feedwater, reverse osmosis (RO), and demineralizer systems.

Since conductivity increases with ion concentration (up to a point), it can correlate to percentage concentration values for solutions such as acids or bases. However, as conductivity is non-specific, percentage concentration measurement is only applicable to individual chemicals, not mixtures of multiple contributing chemicals.

Two primary sensor styles are used for conductivity measurement: Contacting and Inductive (Toroidal, Electrodeless).

Contacting sensors measure conductivity by applying an alternating electrical current to sensor electrodes (which together define the cell constant) immersed in a solution and measuring the resulting voltage. The solution acts as the electrical conductor between the sensor electrodes.

• Polarization: Can influence measurement accuracy
• Contamination: Deposits or coatings on electrode surfaces of 2-pole cells can lower conductivity readings. These effects can be prevented with 4-pole conductivity cells.
• Cable Resistance: Can introduce measurement errors and must be accounted for
• Temperature: Conductivity measurements are temperature-dependent, with conductivity increasing as temperature rises