Most premises outside of the sewered area of the Narrandera township require an on-site waste water disposal system to dispose of liquid wastes in an environmentally acceptable manner. A typical installation for a single dwelling would comprise a house drainage system (Australian Standard 3500), a septic tank and absorption trench or an aerated treated system with a designed disposal area. The proposed work must be approved by Council prior to construction. The designer must prepare a design report and application in accordance with either of the following:

• Australian Standard 1547-1994
• Australian Standard 1547-2000
• The On-Site Waste Water Disposal Guidelines

The design typically needs to consider:

• Soil type
• Disposal site - aspect, proximity to water courses, and adjoining premises
• Pan evaporation data and rainfall
• System design loads

Council's Development and Environment team assess reports, issue consent, and carry out site and construction inspections of on-site waste water disposal systems. Council accepts designs from appropriately qualified, insured and experienced:

• Environmental health officers
• Building surveyors
• Waste water engineers
• Licenced drainers/plumbers

All drainage work must be done by licenced drainers.