Why does distilled water have a much lower conductivity than tap water?

Conductivity is proportional to the number of ions. There must be some kind of particles in our matter containing load and capable to move uming the matter is conductive. These particles could be electrons or ions. In solutions, these particles often are the ions. Tap water contains some kind of compounds which could be some kind of salt or something which is added to it during the purification process. Notice that there is not much of these compounds in our water, so it's not so conductive. Some of these compounds like salt, break into ions and make water conductive. Distilled water lacks these compounds. Because they have taken during the distillation process. No ions, no conductivity.