Azenco’s pergolas gutter system is invisible and control the flows of the rainwater directly into the pergola posts when the louvers are closed. In order to give full performance over time, the gutters may need cleaning to avoid the potential for clogging. We recommend cleaning the gutters at least twice a year, especially if you have trees near your pergola that have falling leaves. It is the owner’s responsibility to make sure the gutter downspouts are not dirty to allow the system to perform at its best. The cleaning process is very easy if done periodically. How to clean the gutters: Use a blower to remove the debris and leaves. Then use clear water with a hose and soft brush combined with any eco-friendly detergent to clean mold or environmental dirt and brush combined with any eco-friendly detergent.