A swimming pool is formed of a plurality of interconnected and contiguous wall and bottom plates some of which are formed with ducts adapted to conduct water into the pool. These plates are formed at the ducts with a plurality of nozzles which direct a flow of water generally upwardly and toward the center of the pool for most efficient water exchange. The ducts are formed as channels between the edges of the contiguous plates and are capped with long cover elements having flanges engaged in grooves in the confronting inside flanks of the channels. The plates are joined together in the duct-forming channels at inwardly bent lips that are bolted together to either side of a resilient seal.

A fluid tight enclosure suitable for use as a swimming pool positioned either above or below ground level, or for relining an existing pool. The enclosure comprises a plurality of waterproof panels forming the side walls and floor, the panels being sealably interconnected by a structure which includes a resilient elastomeric sealing member bridging the adjacent panels and sealably contacting the front faces thereof. A relatively rigid plastic cover member overlies the sealing member, and in one embodiment of the disclosed invention, a relatively rigid plastic base member is positioned to underlie the sealing member, the base member including an upwardly directed flange adapted to operatively engage a conforming portion of the cover member to secure the cover member in it position overlying the sealing member.