What is the purpose of a backflow preventer?

A backflow preventer is an essential device in water distribution systems designed specifically to prevent the reverse flow of water, which can lead to contamination of the potable water supply. When water flows in the opposite direction, it can carry pollutants, chemicals, or other harmful substances into the clean water system. This device is crucial for ensuring the safety and quality of drinking water, protecting public health from potential hazards associated with contaminated water.

In terms of the context of other options, while maintaining water temperature, pressure, or levels are important aspects of water distribution systems, they do not directly relate to the primary function of a backflow preventer. The main purpose is clearly focused on protecting the potable water supply from contamination, which is vital for public health and safety.