The answer to 'why is my irrigation system yellowing' is that the yellowing of your irrigation system is likely caused by mineral buildup, algae growth, or a pH imbalance in the water. This can lead to discoloration and corrosion of the pipes and sprinkler heads.
Some common causes include hard water with high mineral content, using untreated well water, or a lack of regular system maintenance and cleaning. Symptoms may include yellow or orange staining, reduced water pressure, and decreased system efficiency.