Studies revealed that having "1.20" or upper interarm local tissue water (LTW) ratio which can be calculated through tissue dielectric constant (TDC) method might be the determinant of clinical lymphedema after breast cancer surgery. The purpose of this study was to confirm these findings and determine the sensitivity and specificity of LTW (%) measurement method in patients with breast cancer related lymphedema (BCRL). Sixty-three participants were recruited to this study in two groups as follows: the lymphedema group (n = 32), who had BCRL after breast cancer surgery, and the latent group (n = 31), who had breast cancer surgery yet having no lymphedema. LTW (%) measurement of those was conducted with Moisture Meter-D compact (MMDc, Delfin Technologies, Kuopio, Finland) at sites 8 cm proximal (biceps) and 6 cm distal (forearm) from the antecubital fossa, 10 cm inferior from the axilla (lateral thorax) in 2.5 mm depth. Sensitivity and specificity of TDC method were analyzed based on the reference having 1.20 or upper interarm LTW ratio in both groups. Absolute LTW (%) values were significantly different (p < 0.001) between groups in forearm (latent: 26.96 ± 3.35, lymphedema: 36.85 ± 9.32) and in biceps (latent: 26.54 ± 4.11, lymphedema: 36.45 ± 9.91) while in lateral thorax reference point (latent: 35.22 ± 7.44, lymphedema: 33.32 ± 5.08) there was not (p = 0.241). Interarm LTW ratios were significantly different (p < 0.001) between groups in forearm (latent: 1.01 ± 0.06, lymphedema: 1.40 ± 0.35) and in biceps (latent: 1.02 ± 0.10, lymphedema: 1.42 ± 0.38) while in lateral thorax reference point (latent: 1.10 ± 0.25, lymphedema: 1.07 ± 0.16) there was not (p = 0.896). Sensitivity and specificity of the TDC method were 65% and 94%, respectively. Absolute LTW (%) values and interarm LTW ratios were significantly different between patients with clinically diagnosed BCRL and patients with no BCRL (latent group). TDC method has been gradually gaining attention in clinical use and this method might be the preferable method in case of early detection of BCRL in patients in latent phase. Regular follow-ups would be beneficial if objective and sensitive measurement techniques were done in clinical settings.