A waste water insert has a wall surrounding a vertical bore. A horizontal flange extends outwardly from the upper end of the wall and has a lip formed on its outer periphery. The horizontal flange of the waste water insert is super-imposed over the horizontal flange of a waste water strainer located in a bathtub, sink or the like. The wall of the insert extends downwardly through the cylindrical wall of the waste water strainer with the two walls being spaced from each other by virtue of the cylindrical wall of the insert having a smaller diameter than that of the strainer.