A contractor marked flow direction of water is placed on line pipe. In the visible parts and tubing with periodically sign painted by using the following color code when using hose-black grey-sewer pipe air-duct the bile and White-Navy Blue.
The contract marked the direction of flow of water in the pipe line. In the pipeline, and the visible. With a paint marker The color-coded as follows Sewage - black sewer - gray. Air - White CCA - Blue
For contractors mark the flow direction of water on the tube line. Dates in the pipe and the visible. With paint markers for using color coded as follows: Toilet pipes - the black sewers - gray - white air duct bile duct - blue.