What specifications should a house sewer include?

The correct response emphasizes the importance of specific standards in the design and functionality of house sewers. A two-way sanitary clean-out is critical because it allows for proper maintenance and clearing of blockages in both directions—toward the house and toward the municipal sewage system.

The requirement for a minimum diameter of 3 inches ensures adequate flow capacity, reducing the chances of clogs. Additionally, the specification of a minimum fall of 1/8 inch per foot is essential for maintaining proper drainage; it ensures that wastewater flows smoothly downhill, minimizing the risk of backup and potential cross-contamination. This gradient helps prevent stagnation, which can lead to odors and sewer line degradation over time.

In contrast, the other options fail to align with best practices for sewer design. For example, a two-way clean-out with a diameter of less than 3 inches or a one-way clean-out does not provide sufficient capacity or functionality. Moreover, suggesting a simple straight pipe with no clean-outs would severely limit access to the sewer system for maintenance and would likely lead to a host of plumbing issues. Therefore, option C encapsulates the essential specifications for an effective and compliant house sewer design.