The inlet pipe of a grease interceptor shall extend to how many inches below the liquid level?

The inlet pipe of a grease interceptor must extend 18 inches below the liquid level to ensure effective operation of the interceptor. This depth is crucial for several reasons. Firstly, extending the inlet pipe down into the liquid ensures that incoming wastewater is submerged beneath the surface of the grease layer, allowing for proper separation of grease and solids. The submerged inlet helps to minimize turbulence and reduces the chance of grease being carried over to the discharge line.

Moreover, positioning the inlet pipe at this specified depth helps facilitate the settling of heavier solids and prevents them from being disturbed by incoming flow. This ensures that the grease interceptor can efficiently trap fats, oils, and grease (FOG), thereby protecting the plumbing system and the municipal sewer lines from clogs and potential backups.

Meeting this requirement is also essential for compliance with plumbing codes, which mandate specific installation practices to ensure the functionality and longevity of grease interceptors. Implementing the proper depth contributes to sustainability and environmental protection by minimizing the likelihood of FOG entering wastewater systems.