How far must the bottom of the water pipe be above the top of the sewer line?

The correct answer to the question regarding the required distance between the bottom of the water pipe and the top of the sewer line is 12 inches. This 12-inch clearance is a crucial aspect of plumbing code requirements designed to prevent the potential for contamination of potable water by wastewater.

When water pipes are installed above sewer lines, maintaining a minimum distance is essential to ensure that any leaks, spills, or other issues with the sewer line do not compromise the integrity of the drinking water supply. A 12-inch separation helps provide a safety buffer that mitigates risks associated with cross-contamination.

In different plumbing codes, such as the Uniform Plumbing Code and the International Plumbing Code, stipulations regarding the protection of the potable water supply are mandated rigorously, ensuring public health and safety. This requirement is based on the principle of keeping sanitary systems separate from potable systems to avoid health hazards associated with backflow or contamination.

It's important to keep this requirement in mind when designing plumbing systems, as adhering to this standard helps maintain the quality of drinking water and ensures compliance with local and national plumbing regulations.