External Filter Basins (FTB)

Orenco® External Filter Basins are used to retrofit an existing residential septic system with an effluent filter. They eliminate the need for costly and sometimes hazardous modifications to an existing septic tank with restrictive access openings or to unusable outlet baffles or tees. External Filter Basins include a basin, an 8-inch (203-mm) Orenco Effluent Filter, and a grade ring for attaching a section of riser pipe to the basin.

  • 18-inch nominal diameter (450-mm DN) basin
  • Ribbed PVC body
  • Fiberglass reinforced polyester base
  • 12-inch (305-mm) tall, 8-inch (203-mm) diameter, Orenco Effluent Filter included
  • Extendable filter handle for easy removal
  • 4-inch nominal diameter (100-mm DN) inlet and outlet openings
  • Grade ring for 18-inch nominal diameter (450-mm DN) riser pipe included
  • Adapter kit with grommet and 4-inch Type 3034 pipe adapter ordered separately (Product Code FTB3034KIT)
  • 18-inch (450-mm) grade ring ordered separately (See “Grade Rings and Grade Ring Inserts” in this catalog)
  • 18-inch (450-mm) fiberglass access lid ordered separately (see “Fiberglass Access Lids” in this catalog)


Product Codes

  • FTB1824-0812 — Filter basin, 18-inch nominal diameter (450-mm DN), 24-inch (610-mm) height, includes 12-inch (305-mm) tall, 8-inch (203-mm) diameter, Orenco effluent filter
  • FTB3034KIT — Adapter kit with gasket for 4-inch (100-mm) Type 3034 pipe

Technical Data Sheet

Product Sheet

FTB1824-0812 External Filter Basin