Several methods are proposed in literature to characterize the state of deterioration of water-treed cable insulation. One of these methods is the return voltage measurement (RVM) method, which was initially introduced as a diagnostic method for oil-paper insulating systems. It is mostly used to determine the condition of the paper insulation of transformer windings. It has been shown that it is possible to use RVM for detection of water trees in XLPE cables. In this paper, a methodology is presented that allows the detection of water trees in PE and XLPE insulated cables, without the need for a reference measurement. Also, the influence of temperature on RVM measurements was examined, for cables with and without water trees.