Poleski NP is located in the watershed area (of the Bug and the Wieprz rivers); and the natural watercourses (of the Piwonia, the Bobrek, the Mietiulka and the Wlodawka rivers) have been significantly transformed in the last century. At present, only small fragments have preserved their primal character.

The anthropogenic elements are channels: inflowing channel Bogdanka- Wola Wereszczynska and inflowing channel Wola Wereszczynska – Wytyczno Retention Reservoir, and also a dense net of trenches.

The standing waters of the park consist of the Lukie, Torfianka, Krasne, Moszne, and Dlugie Lakes, and ponds. The last ones are located in the two complexes "Bruski" and "Pieszowolski". The areas of the afore-mentioned reservoirs are shown in the table below. Lukie Lake, the biggest lake in the park, has a very shallow basin, the average depth is 1.8 m., the maximal 6.5 m. It is a eutrophic reservoir, surrounded by the strip of reed, bulrush and marshy meadows. In the last years, an intense lake overgrowth with water soldier has been observed. The remaining three lakes: Moszne, Dlugie and Karasne are small, shallow dystrophic reservoirs surrounded by a wide strip of quagmire (“a coat" of turfogenic plants, mainly peat moss). Their basins are shallow and the bottoms are sludgy (gytia). The layer of water is up to 1 m.

Moreover, from the natural point of view, small water reservoirs such as, for example, turf pits and overflow areas and other astatic reservoirs, play a considerable part. The waters in total consist around 5% of the PNP territory