According to the regionalisation drawn up by the Ministry of the Environment,[REF] the Kashubian Lake District lies, as a whole, in the region of the Lower Vistula, and so its waters are subject to RZGW in Gdańsk.
The mesoregion is able to be split in the following river basins: Radunia Reda, Łeba, Motława, Wierzyca, Słupia, and Łupawa.