The scuppers are designed with a drip edge so that water does not run underneath the scupper onto the wall when the flow is turned off. However, it is possible for the patina to stain the surface of the tile or stone should it make contact. To prevent staining, it is important to clean and polish the unit and wipe off the wall regularly. Doing so will help maintain the copper polish and extend the life of the scupper and prevent stains from accumulating on the wall.Staining of the wall can also occur from splash or rainwater runoff.