The invention relates to a sanitary installation (1) with at least one retaining rail (10) which, in a mounted state (Z), extends vertically along a longitudinal extent (L), at least one primary function module (20) which is configured to partition off at least a
shower area (D) and which engages with a primary section (11.1) of the retaining rail (10) along the longitudinal extent (L), wherein the primary function module (20) has a
shower area-side primary function module side surface (23), an opposite room-side primary function module side surface (24), a primary function module height (25) which, in the mounted state (Z), extends parallel to the longitudinal extent (L) and is smaller than the longitudinal extent (L) of the retaining rail (10), and two opposite primary function module end faces (26, 27) extending orthogonally to the primary function module height (25), and with at least one secondary function module (30)which is configured at least to form a sanitary furniture (32) and engages with a secondary section (12) of the retaining rail (10) along its longitudinal extent (L), wherein the secondary function module (30) has a
shower-side secondary function module side surface (33), an opposite room-side secondary function module side surface (34), a secondary function module height (35) extending parallel to the longitudinal extent (L) in the assembled state (Z), which is smaller than the longitudinal extent (L), and two opposite secondary function module end faces (36, 37) extending orthogonally to the longitudinal extent (L). The invention proposes that at least a first primary function module end face (26) is at least indirectly in contact with a first secondary function module end face (36), such thatthat the primary
functional module side surface (23) facing the shower area and the secondary
functional module side surface (33) facing the shower area form a contiguous surface (A).