What does the "purple pipe" designation indicate?

The "purple pipe" designation indicates non-potable recycled water. This color coding is used as a safety measure to help differentiate between potable (safe for drinking) and non-potable water sources in the distribution systems. Non-potable recycled water is treated water that is reused for various applications such as irrigation, industrial processes, and toilet flushing, but is not safe for human consumption. The purple coloring serves to clearly identify this water for proper use and to prevent accidental cross-connection with potable water supplies. This distinction is important in preventing contamination and ensuring public health safety. The other choices refer to different types of water systems, which do not specifically use the "purple pipe" designation.