Here's why:

* Dissolved Minerals: Mineral water contains dissolved minerals like calcium, magnesium, sodium, and potassium. These minerals exist as ions in solution, meaning they have a positive or negative charge.

* Charge Carriers: These charged ions act as charge carriers, allowing electricity to flow through the water.

* Conductivity Varies: The conductivity of mineral water varies depending on the concentration of dissolved minerals. Higher mineral content generally means higher conductivity.

Important Note: While mineral water is a conductor, its conductivity is usually much lower than that of tap water, which often contains higher levels of dissolved minerals.