Resistivity

Definition

The inverse-of-conductivity measure used to characterize very pure water, where ultrapure water reaches about 18.2 megaohm-cm.

Ultrapure water resistivity of 18.2 MΩ·cm corresponds to roughly 0.055 microS/cm of conductivity. High resistivity signals very few charge carriers and therefore very low dissolved ionic content. It is the practical measure for verifying high-purity water from demineralization or polishing.

Related concepts

Conductivity · Dissolved Solids

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Part of The Blueprint of Water · 📏 measurement