Conductivity

Conductivity is a property, not a contaminant. EPA defines it as "a measure of the ability of water to pass an electrical current", and explains that "dissolved salts and other inorganic chemicals conduct electrical current" — so the reading rises with dissolved mineral content. It is usually reported in micromhos or microsiemens per centimetre (µmhos/cm or µS/cm). EPA notes that "each water body tends to have a relatively constant range of conductivity that, once established, can be used as a baseline for comparison". There is no EPA drinking-water limit for conductivity; because it tracks dissolved solids, it is often used as a proxy for total dissolved solids, which does carry an EPA secondary standard of 500 mg/L.

Source: EPA — National Aquatic Resource Surveys — Indicators (retrieved 2026-07-27)

Water filters certified under the following NSF standards are effective at removing Conductivity: