What type of cleanout is often used in building sewers for effective maintenance?

The two-way cleanout is commonly used in building sewers because it allows access to the sewer line from both directions. This is particularly important for effective maintenance and cleaning, as it provides a way to clear blockages and facilitate inspection from either end of the sewer line. The design of the two-way cleanout allows maintenance personnel to insert a cleaning tool or camera from either direction, making it versatile and efficient for addressing clogs or performing routine maintenance.

In contrast, a single cleanout only provides access in one direction, which may limit its effectiveness in specific situations where blockages occur further down the line. A horizontal cleanout is designed for use when the piping is laid out horizontally, but it may not enable the same level of access as a two-way cleanout. A vertical cleanout is oriented upward and is primarily used in vertical stacks or at intervals in vertical lines, and while it is valuable for access, it doesn't provide the two-directional access that a two-way cleanout offers. Therefore, the two-way cleanout is the best option for comprehensive maintenance in building sewer systems.