The Waterco Baker Hydro HRV 18 Drain Assembly is a filter-system service part used on compatible sand, cartridge, or specialty filter assemblies. Parts in this group may support sealing, internal distribution, debris collection, water routing, lid service, or pressure monitoring depending on the component. Correct fit is important because filter parts often depend on tank size, model family, lid style, internal pipe layout, or threaded connection. Inspect the existing part for cracks, distortion, worn sealing surfaces, or missing hardware, and compare the replacement by part number and dimensions before installation. Manufacturer or brand reference: Waterco USA. Part number: 16B0309. Designed for compatible Waterco USA equipment or replacement applications Useful for replacing a worn, damaged, missing, or service-aged original component Helps support filtration performance when matched to the correct housing or system Verify dimensions, end style, tank model, or cross-reference before ordering Part number 16B0309 should be used as the primary compatibility reference