What is the minimum horizontal separation distance required between water service pipe and the building sewer?

The minimum horizontal separation distance required between water service pipes and building sewers is typically set at 5 feet. This requirement is in place to ensure that there is sufficient separation to prevent contamination of the potable water supply. The primary concern is that if a sewer line experiences a leak or failure, it may allow untreated wastewater to infiltrate the surrounding soil and potentially reach the water service pipe.

Separating these two systems by at least 5 feet helps mitigate this risk by minimizing the possibility of cross-contamination. Additionally, the distance provides a buffer zone that allows for safer maintenance and access to either utility without compromising the other.

Standards and codes like the International Plumbing Code include these distances as part of good plumbing practice to protect public health and safety. While other distances may be specified in different contexts or for other utilities, in this case, the 5-foot requirement acts as a safeguard against potential hazards associated with inadequate separation.