What is the typical slope recommended for building sewer lines to ensure proper drainage?

The typical slope recommended for building sewer lines is between 2% to 3%. This range is considered optimal for ensuring that wastewater flows efficiently through the sewer line without causing blockages. A slope of 2% (which equates to 2 cm of drop per 100 cm of horizontal run) provides sufficient gravitational force to move solids and liquids while minimizing the potential for sediment buildup. A steeper slope, such as 3%, also promotes efficient drainage, but if the slope is too steep, it can create turbulence in the flow, which might cause solids to be carried away too quickly and not allow for proper drainage throughout the system.

While a slope of 1% might not be steep enough to ensure effective flow, and slopes of 4% and higher could lead to excessive velocity that may result in erosion of the pipe material or loss of solids, the 2% to 3% range strikes a balance, allowing for effective waste transport while minimizing the risk of issues in the drainage system.