System for detecting the level of a well or tank comprising: an electric immersion pump, having a vertical extension in the configuration for use and comprising a containment shell inside which there are: - a wet section, which comprises an intake portion and a delivery portion and one or more impellers keyed on a shaft, each with its own diffuser, and interposed between said intake portion and said delivery portion, - an electromechanical section, which comprises motor means for the movement of said shaft, - an electronic section, comprising a compartment inside which an assembly for the control and actuation of said electric immersion pump is contained, said control and actuation assembly being provided with an electrical board, a device, at least partially integrated in the electric immersion pump, for detecting the level of a well or tank comprising: - a management and control element, of the electronic type, - a first portion, comprising an air pressure sensor, physically/electrically connected to said management and control element, - a second portion, which comprises a pressure transducer and is connected to said management and control element by means of a wireless connection, wherein said control and actuation assembly is connected to a user interface of said electric immersion pump and comprises communication means of the NFC type, said communication means being connected electrically to said user interface and/or to said management and control element of said device, said second portion of said device comprises complementary communication means of the NFC type, and said communication means are arranged proximate to a receptacle, said receptacle being internal to said electronic section and being accessible from the outside of said shell, said receptacle being external to said compartment, said second portion of said device being inserted in said receptacle at least at said complementary communication means an electric immersion pump, having a vertical extension in the configuration for use and comprising a containment shell inside which there are: - a wet section, which comprises an intake portion and a delivery portion and one or more impellers keyed on a shaft, each with its own diffuser, and interposed between said intake portion and said delivery portion, - an electromechanical section, which comprises motor means for the movement of said shaft, - an electronic section, comprising a compartment inside which an assembly for the control and actuation of said electric immersion pump is contained, said control and actuation assembly being provided with an electrical board, a device, at least partially integrated in the electric immersion pump, for detecting the level of a well or tank comprising: - a management and control element, of the electronic type, - a first portion, comprising an air pressure sensor, physically/electrically connected to said management and control element, - a second portion, which comprises a pressure transducer and is connected to said management and control element by means of a wireless connection, - a wet section, which comprises an intake portion and a delivery portion and one or more impellers keyed on a shaft, each with its own diffuser, and interposed between said intake portion and said delivery portion, - an electromechanical section, which comprises motor means for the movement of said shaft, - an electronic section, comprising a compartment inside which an assembly for the control and actuation of said electric immersion pump is contained, said control and actuation assembly being provided with an electrical board, a device, at least partially integrated in the electric immersion pump, for detecting the level of a well or tank comprising: - a management and control element, of the electronic type, - a first portion, comprising an air pressure sensor, physically/electrically connected to said management and control element, - a second portion, which comprises a pressure transducer and is connected to said management and control element by means of a wireless connection, - a management and control element, of the electronic type, - a first portion, comprising an air pressure sensor, physically/electrically connected to said management and control element, - a second portion, which comprises a pressure transducer and is connected to said management and control element by means of a wireless connection, wherein said control and actuation assembly is connected to a user interface of said electric immersion pump and comprises communication means of the NFC type, said communication means being connected electrically to said user interface and/or to said management and control element of said device, said second portion of said device comprises complementary communication means of the NFC type, and said communication means are arranged proximate to a receptacle, said receptacle being internal to said electronic section and being accessible from the outside of said shell, said receptacle being external to said compartment, said second portion of said device being inserted in said receptacle at least at said complementary communication means