A wall element for holding back water is formed in one piece and has a planar, rectangular main portion having a first side, a second side parallel to the first side, a third side perpendicular to the first side, and a fourth side parallel to the third side. A first planar bearing portion is connected to the main portion over the first side and perpendicular to the main portion. A second planar bearing portion is connected to the main portion over the second side and perpendicular to the main portion. The second bearing portion is opposite the first bearing portion. The wall element has a planar connecting portion connected to the main portion over the third side and inclined to the main portion. The connecting portion has connecting holes in the longitudinal direction, and the main portion has connecting holes along the longitudinal extent of the fourth side.