A use of infrared thermography for quantitative evaluation of water hidden in honeycomb cells is discussed. Test case modeling has been performed by analyzing a 3D honeycomb panel model where water fully or partially occupies cells. Calculation of several test cases has allowed to better understand how the thickness of the water layer adjacent to an inspected skin, or the thickness of the air gap between skin and water, affects temperature anomalies and times of their appearance in active thermal tests. Experimental results have been obtained on both reference and real samples.