This paper presents a performance assessment of Time Domain Reflectometry (TDR) and Frequency Domain Reflectometry (FDR) to locate water trees on single core XLPE cable's insulation. Three different scenarios were evaluated on each technique. The first scenario verifies the correct operation of TDR and FDR. The second scenario evaluates if each technique was able to detect a water tree at different stages on its growth through cable's insulation. Finally, the third scenario evaluates if each technique was able to locate two water trees, at different stages, on the same cable.