Council operates and maintains three effluent disposals (sewerage) systems within the Carrathool Shire LGA. Carrathool and Merriwagga remain un-sewered and have septic tanks.

Hillston Sewerage System
The Hillston Sewerage System constructed in the early 1970s, comprises a conventional gravity reticulation system which is divided into seven catchments and pressure sewer on outskirt where gravity sewer is not available. Wastewater from various catchment areas is pumped into Sewage pumping station five on Keats Street for subsequent transfer to the Hillston Sewage Treatment Plant (STP) located to the east of Hillston.

At the STP, sewage undergoes secondary biological treatment in an extended aeration process.  The resulting treated effluent is then disposed of in an evaporation pond at the STP site.

Goolgowi Sewerage Scheme
The Goolgowi Sewerage System constructed in the early 1970s, comprises a conventional gravity reticulation system, which is divided into five (5) catchments areas. Wastewater is subsequently transfers to storage ponds for evaporation.

Rankins Springs
The Rankins Springs village has a sullage System that is comprised of a network of reticulation pipes, one sewer well and pump station. Onsite treated household waste gravitates to the pump station and is subsequently pumped into sullage ponds for evaporation.

Waste water from the Water Treatment Plant is also pumped via a separate system into sullage ponds for evaporation.