The answer to 'why is my irrigation system yellowing' is that the yellowing of your irrigation system is likely due to mineral buildup or bacterial growth. This can occur when water with high mineral content, such as hard water, is used in the system. Over time, these minerals and bacteria can accumulate on the components, causing them to discolor and become less efficient.
Some common symptoms of a yellowing irrigation system include discolored sprinkler heads, valves, and pipes, as well as reduced water pressure and uneven water distribution. If left untreated, this issue can lead to further damage and costly repairs.