A hydro-cleaning system (1000, 1001, 2001) in particular apt to the cleaning of a WC, comprising a jet device (120, 2000) having: - a hollow cylindrical body, apt to contain a liquid; - a nozzle, removably connected or connectable to a first terminal end of said hollow cylindrical body; - a piston, associated to said hollow cylindrical body, comprising a driving rod, apt to slide according to a translation movement, integral to a plunger, said plunger being movable according to an approaching/distancing translational movement from said first terminal end of said hollow cylindrical body, said approaching movement being associated to a liquid emission phase from said nozzle, and wherein said plunger defines a first room and a second room of said hollow cylindrical body, at said first and second terminal end thereof, respectively; - a first unidirectional valve, removably connected or connectable to said nozzle at a passage section of said liquid, oriented so as to allow the emission of said liquid from said hollow cylindrical body and to prevent the inlet of said liquid in said hollow cylindrical body; - a bottom removably connected or connectable to said hollow cylindrical body at a second terminal end of said hollow cylindrical body, having a hole with guiding members, apt to allow a sliding of said driving rod; - a return elastic member placed so as to withdraw the piston in a position of maximum distance from said first terminal end characterized by: - a reversible locking mechanism of the piston with respect to said hollow cylindrical body, comprising a magnetic locking system; and - a releasing system for said reversible locking mechanism, wherein said magnetic locking system comprises one or more magnets placed near the bottom and a corresponding attraction member positioned at a first end of said rod opposite to said plunger, apt to be attracted by said one or more magnets. - a hollow cylindrical body, apt to contain a liquid; - a nozzle, removably connected or connectable to a first terminal end of said hollow cylindrical body; - a piston, associated to said hollow cylindrical body, comprising a driving rod, apt to slide according to a translation movement, integral to a plunger, said plunger being movable according to an approaching/distancing translational movement from said first terminal end of said hollow cylindrical body, said approaching movement being associated to a liquid emission phase from said nozzle, and wherein said plunger defines a first room and a second room of said hollow cylindrical body, at said first and second terminal end thereof, respectively; - a first unidirectional valve, removably connected or connectable to said nozzle at a passage section of said liquid, oriented so as to allow the emission of said liquid from said hollow cylindrical body and to prevent the inlet of said liquid in said hollow cylindrical body; - a bottom removably connected or connectable to said hollow cylindrical body at a second terminal end of said hollow cylindrical body, having a hole with guiding members, apt to allow a sliding of said driving rod; - a return elastic member placed so as to withdraw the piston in a position of maximum distance from said first terminal end characterized by: - a reversible locking mechanism of the piston with respect to said hollow cylindrical body, comprising a magnetic locking system; and - a releasing system for said reversible locking mechanism,