Abstract: The invention concerns a method for assembling components for water retention tanks, such as swimming pools for example, characterised in that it consists in: producing parts or elements of the pool or shell (1) with one edge (7) oriented outwards, over at least part of their periphery, and outer structural elements (2, 3a, 3b, 4) with a groove (8) oriented inwards; providing a sealing joint (9) at the bottom of said groove; and engaging therein the adjacent outer edges (7) of two contiguous shell elements (1), such that they are urged to rest on said joint (9), under the pressure of water introduced in the pool thereby assembling the set of shell (1) elements, and thus producing the junction of said shell (1) parts or elements and sealing said junction.