The investigation was carried out concerning the capacity and water retention of the hydrogel "HIDROPLUS". This is a kind of synthetic polymeric compound, sodium acrylate, of grain dimension of 1-3 mm. The gel was saturated with water to reach the full water capacity. and after 24 hours, the samples were taken to be placed in cylindrical containers or 100 cm³ Then the measurements were carried out in low-pressure apparatus, on porous ceramic plates. The water content was determined in the gel samples (within the range of potential from –0.98 up to –49.03 kPa). The measurement was done at the low values of water potential, in high-pressure apparatus. The maximum gel hygroscopic properties value was determined in a vacuum dessicator. In virtue of the results received a characteristics was prepared, concerning the dependence of water content on water potential. Then the retention values were found and the contribution of various categories of soil water in it. Full water capacity of the gel is quite considerable. The minimum contribution of this water belongs to the gravitational water, the maximum to the adsorption water, unavailable for plants. As for the available water, a bit more than half of it, is the water ve1y easy available for plants. Most of the water properties of the studied gel should be described as positive ones but, at the same time, a considerable part of its water is so strongly bound to it that the plant roots are unable to take it, or they hardly do so. In the mixture with the other materials, the gel saturated with water, is, at first, the source of water for plants. Then, as it gets dried, it becomes a kind of competitive material for them to get water.