A sectional modular system for making sanitary plumbing fixtures of the type comprising: - one or more base components which are designed to be placed in a wall in an embedded, semirecessed or externally mounted position and to be put in fluid communication with each other and/or with a water distribution line; - at least one removable component selected from the group comprising: a two- or more way diverter, a mixer, a mechanical and/or motorized thermostatic mixer, a fluid shut-off valve means, a multiple-way regulator/diverter and a water delivery outlet with which a wash basin or tub spout, a shower head, a rinsing spray set may be connected, and - a support and centering structure designed to be mounted to said wall, for supporting two or more base components to ensure proper placement and relative position thereof, wherein: - each removable component is associated in fluid communication with a respective base component; - said one or more base components comprise a body having a front wall which is designed to face toward the back wall of their respective removable component, a back wall opposite thereto, and side walls; - each removable component comprises rear water passages at said back wall; - the body of said one or more base components is divided into a plurality of independent water chambers (14, 15); characterized in that: - said front wall of the body of the one or more base components is prearranged with front water passages, for putting a respective water chamber (14, 15) of the base component in fluid communication with a corresponding rear water passage of a removable component; - said plurality of independent water chambers comprises a first water chamber and at least four remaining water chambers; - each water chamber (14, 15) is prearranged to have at least two lateral water passages at said side walls of the body of said one or more base components. - one or more base components which are designed to be placed in a wall in an embedded, semirecessed or externally mounted position and to be put in fluid communication with each other and/or with a water distribution line; - at least one removable component selected from the group comprising: a two- or more way diverter, a mixer, a mechanical and/or motorized thermostatic mixer, a fluid shut-off valve means, a multiple-way regulator/diverter and a water delivery outlet with which a wash basin or tub spout, a shower head, a rinsing spray set may be connected, and - a support and centering structure designed to be mounted to said wall, for supporting two or more base components to ensure proper placement and relative position thereof, wherein: - each removable component is associated in fluid communication with a respective base component; - said one or more base components comprise a body having a front wall which is designed to face toward the back wall of their respective removable component, a back wall opposite thereto, and side walls; - each removable component comprises rear water passages at said back wall; - the body of said one or more base components is divided into a plurality of independent water chambers (14, 15); characterized in that: - said front wall of the body of the one or more base components is prearranged with front water passages, for putting a respective water chamber (14, 15) of the base component in fluid communication with a corresponding rear water passage of a removable component; - said plurality of independent water chambers comprises a first water chamber and at least four remaining water chambers; - each water chamber (14, 15) is prearranged to have at least two lateral water passages at said side walls of the body of said one or more base components.