When installing a horizontal soil line, a clothes washer branch connection may not be connected closer than _____________ feet downstream from a water closet opening.

The requirement that a clothes washer branch connection must not be installed closer than 5 feet downstream from a water closet opening is important for several reasons related to plumbing design and function.

A horizontal soil line conveys wastewater from various fixtures, including toilets and washing machines. The minimum distance helps to prevent potential backflow, which could lead to contamination of the clothes washer's drainage system. If the branch connection is too close to the water closet, there is an increased risk of improper drainage and foul odors due to the proximity of the washing machine to the toilet's waste line. This distance ensures that any negative pressure or surges created by the flushing of the toilet do not adversely affect the washing machine’s functionality or hygiene.

Furthermore, maintaining this distance allows proper venting and airflow within the plumbing system, which is crucial for maintaining effective drainage and preventing clogs. Therefore, adhering to this code not only supports the integrity of the plumbing system but also ensures compliance with health and safety standards that are established within the Omaha Plumbing Code.