A system for treating water comprising: at least one electrochemical water treatment unit comprising a first self-supporting framework having the outer form of a cuboid and limiting a first inner space, wherein at least one electrochemical reactor is arranged in the first inner space, wherein said at least one electrochemical reactor comprising at least one electrode module releasable arranged in said at least one electrochemical reactor, wherein said at least one electrochemical water treatment unit comprising a top side, a bottom side, a pair of end sides and a pair of sides, wherein said at least one electrochemical water treatment unit comprising first opening in the top side, and wherein said at least one electrochemical reactor being arranged in the first inner space of said at least one electrochemical water treatment unit vertically below the first opening in the top side, a maintenance unit comprising second self-supporting framework having the outer form of a cuboid and limiting a second inner space, wherein the maintenance unit comprising a top side, a bottom side, a pair of end sides and a pair of sides, and wherein the maintenance unit comprising a second opening in the bottom side, the maintenance unit being configured to be arranged above said at least one electrochemical water treatment unit so that the first opening in the top side of said at least one electrochemical water treatment unit and the second opening in the bottom side of the maintenance unit are aligned and so that a section of the maintenance unit is unsupported by said at least one electrochemical water treatment unit, a third opening in the bottom side in said section of the maintenance unit, and a hoist movable arranged along a rail structure at the top side of the maintenance unit in the second inner space of the maintenance unit, so that the hoist is movable to a position above the second opening in the bottom side of the maintenance unit and to a position above the third opening in the bottom side of the maintenance unit. at least one electrochemical water treatment unit comprising a first self-supporting framework having the outer form of a cuboid and limiting a first inner space, wherein at least one electrochemical reactor is arranged in the first inner space, wherein said at least one electrochemical reactor comprising at least one electrode module releasable arranged in said at least one electrochemical reactor, wherein said at least one electrochemical water treatment unit comprising a top side, a bottom side, a pair of end sides and a pair of sides, wherein said at least one electrochemical water treatment unit comprising first opening in the top side, and wherein said at least one electrochemical reactor being arranged in the first inner space of said at least one electrochemical water treatment unit vertically below the first opening in the top side, a maintenance unit comprising second self-supporting framework having the outer form of a cuboid and limiting a second inner space, wherein the maintenance unit comprising a top side, a bottom side, a pair of end sides and a pair of sides, and wherein the maintenance unit comprising a second opening in the bottom side, the maintenance unit being configured to be arranged above said at least one electrochemical water treatment unit so that the first opening in the top side of said at least one electrochemical water treatment unit and the second opening in the bottom side of the maintenance unit are aligned and so that a section of the maintenance unit is unsupported by said at least one electrochemical water treatment unit, a third opening in the bottom side in said section of the maintenance unit, and a hoist movable arranged along a rail structure at the top side of the maintenance unit in the second inner space of the maintenance unit, so that the hoist is movable to a position above the second opening in the bottom side of the maintenance unit and to a position above the third opening in the bottom side of the maintenance unit.