CSLB Class B General Contractor's License Practice Exam

What is the main purpose of using purple pipes in plumbing systems?

1. To transport potable water

2. To carry non-potable water

3. For fire suppression systems

4. For stormwater drainage

The correct answer is: To carry non-potable water

The main purpose of using purple pipes in plumbing systems is indeed to carry non-potable water. Purple pipes are specifically colored to denote that they are designated for reclaimed or recycled water, which is water that has been treated to a degree that makes it safe for certain uses but is not considered safe for drinking. This visual identification helps prevent cross-connections with the potable water supply, ensuring that non-potable water is not mistakenly used for drinking, cooking, or bathing. Purple pipes are often used in irrigation systems, industrial processes, or toilet flushing systems, where high-quality drinking water is not necessary. The use of color-coded systems like purple pipes plays a critical role in maintaining public health and achieving sustainable water management practices. In this context, using colors helps workers and the general public quickly identify the intended use of the piping, preventing potential health hazards associated with using treated wastewater for inappropriate purposes.