Water-drainage device for a sanitary installation, such as a floor-level shower area, comprising: - a channel covering, - a channel-like drainage region having a centrally arranged water-outflow opening and a water-inflow opening, which runs towards the water-outflow opening, - a transition region, which is arranged within the channel-like drainage region and has an odour-seal system and at least one drainage connector through which water can exit, wherein the odour-seal system comprises a housing, with an inner chamber and at least one outer chamber, and a bell element, which penetrates into the housing, wherein the outer chamber is delimited, at least in part, by a housing wall, - wherein the bell element is a hollow body, - wherein, as seen in plan view of a floor of the housing, the inner chamber is formed by an encompassing, first blocking wall and, with the exception of the through-passage region to the drainage connector, is enclosed entirely by the outer chamber, - wherein a central chamber is arranged between the inner chamber and the outer chamber - with the bell element inserted, - wherein the outer chamber is separated by the second blocking wall from the central chamber and the central chamber is separated by the first blocking wall from the inner chamber, and the flow direction of the waste water is directed from the outer chamber to the central chamber, from there to the inner chamber, and from there to the drainage connector, characterized in that - the bell element has an elongate, rectilinearly running apex region, two likewise elongate side walls (49, 50) and two further side walls (55, 56), which are located on the narrow sides of the hollow body and form a second blocking wall, - as seen in plan view of the floor, the central chamber, with the exception of the through-passage region to the drainage connector, is enclosed entirely by the second blocking wall, and therefore the chambers (34, 33, 32) are formed by the housing wall and by blocking walls (36, 35) situated around one another in ring form, and - wherein the blocking wall of the bell element has an aperture, and therefore the bell element can be fitted over the inner chamber and the drainage connector, which extends from the inner chamber. - a channel covering, - a channel-like drainage region having a centrally arranged water-outflow opening and a water-inflow opening, which runs towards the water-outflow opening, - a transition region, which is arranged within the channel-like drainage region and has an odour-seal system and at least one drainage connector through which water can exit, wherein the odour-seal system comprises a housing, with an inner chamber and at least one outer chamber, and a bell element, which penetrates into the housing, wherein the outer chamber is delimited, at least in part, by a housing wall, - wherein the bell element is a hollow body, - wherein, as seen in plan view of a floor of the housing, the inner chamber is formed by an encompassing, first blocking wall and, with the exception of the through-passage region to the drainage connector, is enclosed entirely by the outer chamber, - wherein a central chamber is arranged between the inner chamber and the outer chamber - with the bell element inserted, - wherein the outer chamber is separated by the second blocking wall from the central chamber and the central chamber is separated by the first blocking wall from the inner chamber, and the flow direction of the waste water is directed from the outer chamber to the central chamber, from there to the inner chamber, and from there to the drainage connector, - the bell element has an elongate, rectilinearly running apex region, two likewise elongate side walls (49, 50) and two further side walls (55, 56), which are located on the narrow sides of the hollow body and form a second blocking wall, - as seen in plan view of the floor, the central chamber, with the exception of the through-passage region to the drainage connector, is enclosed entirely by the second blocking wall, and therefore the chambers (34, 33, 32) are formed by the housing wall and by blocking walls (36, 35) situated around one another in ring form, and - wherein the blocking wall of the bell element has an aperture, and therefore the bell element can be fitted over the inner chamber and the drainage connector, which extends from the inner chamber.