What is the minimum elevation difference required for the house sewer?

The minimum elevation difference required for the house sewer is calculated based on the length of the sewer line. This approach follows the standard practice of ensuring that there is adequate slope for efficient drainage and proper wastewater flow. The guideline suggests that for every 8 feet of horizontal run, there should be at least a 1-foot drop in elevation, which is calculated by dividing the length of the sewer line in feet by 8. This ensures that gravity effectively facilitates the movement of wastewater through the system and minimizes the risk of backups or blockages.

The other options do not provide a standardized and effective way to determine the necessary elevation difference for sewer lines. Some of them may not align with best practices for drainage and can result in inefficient wastewater management. For optimal functioning of an on-site sewage facility, adhering to the length-to-slope ratio is crucial in avoiding potential issues.