When constructing offshore pipelines, the concreting of pipes is used as a protective and weighting structure. The requirements for concrete water absorption are set only to ensure the corrosion resistance of concrete. When determining the design characteristics of the structures described above, it is not taken into account that the water-saturated concrete has an increased ballasting capacity, which makes it possible to ensure the stability of the design spatial position of the main gaspipeline of underwater crossings for the entire period of operation of the gas pipeline. Determining the actual water absorption of concrete under pressure can reduce the volume of concrete used, as well as reduce the cost of ballasting while ensuring the stable position of the pipeline. This article describes a new developed technique for determination of the water absorption of concrete under water pressure based on the UVF-6/09 unit. The obtained experimental data of the water absorption of concrete at various values of water pressure are shown. An analysis of the results of experimental work is given.