Electrical conductivity of pure water

Definition

Chemically pure water carries a small but nonzero electrical conductivity around 0.055 microsiemens per centimeter. This conductivity comes from the tiny population of hydrogen and hydroxide ions formed by self-ionization.

Even perfectly pure water is never chemically empty; it continually forms ions by reacting with itself. The measured conductivity is direct evidence of self-ionization. The value is the practical baseline for high-purity water and a sign of how few ions exist at neutrality.

Related concepts

Self-ionization of water · Neutral pH

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Part of The Blueprint of Water · 📏 measurement