What is the ideal type of connection for a sewer lateral to a sewer mainline?

The ideal type of connection for a sewer lateral to a sewer mainline is a wye connection. This configuration allows for a smooth transition and efficient flow of wastewater from the lateral to the mainline. The wye connection is designed at an angle, typically around 45 degrees, which minimizes the risk of turbulence and allows for better drainage.

The wye design also facilitates easier maintenance and cleaning operations, as it reduces the chances of blockages at the junction where the lateral meets the mainline. Additionally, this connection supports the natural flow and helps maintain proper hydraulic characteristics within the sewer system.

Other connection types like elbows, crosses, and reducers can create more abrupt changes in direction or diameter, which may lead to greater resistance to flow and potential areas for blockage, making these options less ideal for connecting laterals to mainlines.