Distilled water is a weak electrolyte due to very low concentration of mobile ions. It is rather a dielectric due to its poor conductivity (since dielectrics are mainly insulators). However tap water contains dissolved impurities which conduct on application of electric field. This water is rarely soft as it contains Ca^2+, Mg²⁺, SO₄^2- etc. When tap water is electrolyzed (with or without addition of other electrolytes) numerous compounds may be obtained. Here the source of current (a battery or a transformer with a rectifier) is very important as it affects the products greatly. This paper has attempted to describe electrolysis of tap water in synthesizing compounds like CuOH (stable only for about 1-2 seconds), Cu(OH)₂, Cu₂O, CuCO₃.Cu(OH)₂, colloidal solution of graphite and that of copper. We used tap water, copper wire, NaCl, Pb(CH₃COO)₂ as the raw materials. As for the source of current we used a 9V battery and a step down transformer (12V/3A) depending on the products. The same solution (e.g. NaCl solution) when electrolyzed by two different currents, one pure D.C. and the other containing A.C. components gives totally different products. Thus A.C. components in a source of D.C. can be detected.