What issue may arise from flatter sewer line grades?

Flatter sewer line grades can result in an increased odor nuisance due to inadequate flow velocity within the pipes. When the grade is too flat, wastewater flows more slowly, leading to stagnation in parts of the sewer system. This stagnation allows for the accumulation of waste and can create conditions that promote the production of odorous gases, such as hydrogen sulfide. Proper sewer line grades are essential to ensure that waste moves swiftly through the system, helping to minimize odor issues by preventing debris build-up and ensuring gases are more effectively ventilated. Stagnation, on the other hand, can lead to a more pronounced odor problem, making it an important consideration in the design and maintenance of sewer systems.