Rural properties in the Port Macquarie-Hastings hinterland, from the Comboyne Plateau to the King Creek-Beechwood corridor, typically rely on two independent systems that most homeowners treat separately: water supply (rainwater tanks, bores, or creek access) and on-site sewage management (septic or AWTS). The reality is that these systems are deeply interdependent. Getting either one wrong can contaminate your drinking water, violate NSW health and environment legislation, or make your property unliveable.
Quick answer (BLUF)
When planning an off-grid property, your septic or AWTS system must be sited with safe separation from every water supply, rainwater tank, bore, and any surface water. NSW Health and the NSW EPA set minimum setback distances, but local soil conditions, topography, and the Hastings River catchment’s sensitivity mean you often need greater separation than the minimum. Always design both systems together, not sequentially.
Why water supply and sewage must be planned together
The most common costly mistake on new rural properties is designing the house footprint, driveway, and rainwater tank first, then trying to fit a septic system into whatever land is left. This creates two problems:
- Inadequate setbacks: The septic system ends up closer to water infrastructure than regulations permit, requiring redesign or forcing a compromise on system location.
- Topographic conflict: Effluent dispersal areas need to be downslope of water supply infrastructure. On sloped Hastings hinterland blocks, this requires careful site analysis.
Port Macquarie-Hastings Council’s OSSM approval process requires that both systems are considered as part of the site assessment.
Water supply options and their septic implications
Rainwater harvesting
Rainwater tanks are the most common water supply on rural Hastings properties. They are relatively simple from a septic planning perspective, the key requirement is maintaining the required separation distance between any septic infrastructure (tank, trenches, irrigation areas) and the tank inlet or overflow dispersal area.
NSW Health’s Private Water Supply Guidelines recommend a minimum 6-metre separation from septic systems; PMHC and the AS/NZS 3500.5 standard may specify greater distances depending on soil type and rainfall intensity.
Importantly, roof catchment should not include areas over or immediately adjacent to septic ventilation pipes or any odour-emitting infrastructure.
Groundwater bores
Bores add complexity because the risk pathway is direct subsurface contamination. Pathogens and nitrates from septic effluent can travel through soil to groundwater at distances that depend on soil permeability, hydraulic gradient, and the depth of the aquifer.
NSW Health guidelines require a minimum 50-metre separation between a septic system absorption area and a groundwater bore used for drinking water, and this is an absolute minimum. In sandy or fractured rock aquifer areas (common in parts of the Hastings region), greater separation is recommended. The bore must also be upslope of the septic system where topography permits.
See our dedicated guide on septic and water bore safe distances for detailed guidance.
Creek and surface water access
Some rural Hastings properties draw supplementary water from the Hastings River system, its tributaries, or farm dams. All are subject to NSW Water Management Act water access licences. From a septic perspective, the Hastings River catchment is a sensitive waterway, PMHC and the NSW EPA apply strict setback requirements from watercourses, which directly affects where your absorption area can be located.
Designing the layout: practical sequence
If you’re developing a raw block or significantly reconfiguring an existing rural property, the recommended planning sequence is:
- Topographic survey, understand slope, drainage lines, flood risk, and the likely paths of subsurface water movement.
- Soil assessment, percolation testing and soil profile assessment across the potential septic area is required for PMHC OSSM approval. Different parts of your block may have dramatically different suitability.
- Identify all water infrastructure locations, tanks, bores, dams, creeks, and neighbouring water sources.
- Map the exclusion zones, apply all required setbacks from each water source to determine where septic infrastructure can legally and safely go.
- Fit the septic design into compliant areas, if the remaining useable area is small or has poor soils, this is when you consider AWTS (which has a smaller absorption footprint) or alternative dispersal methods like subsurface drip irrigation.
- Lodge the OSSM application with PMHC, with completed soil assessment, system design, and site plan.
Special considerations for the Hastings region
Bushfire-prone land: Large parts of the Hastings hinterland (Comboyne, Beechwood, upper Wauchope) are in bushfire-prone areas. Water storage for bushfire protection is a competing land use, and its placement needs to be reconciled with septic setbacks.
Flooding: Low-lying areas near the Hastings River and coastal lagoons (Lake Cathie, Camden Haven) may be subject to flood overlays that further restrict where septic infrastructure can be installed.
Lot size and shape: Smaller rural residential lots (1-5 ha) in areas like King Creek and Beechwood may have difficulty meeting all setback requirements on a single title, particularly if the block has significant vegetation, drainage lines, or irregular shape. An AWTS with spray or drip irrigation often provides the flexibility to make the site work.
Comboyne Plateau: The high-rainfall environment (>2,000 mm/yr) and high water tables on the plateau mean soil saturation is a recurring constraint. Raised mound systems or AWTS with drip dispersal are often the only viable solution in high-water-table areas.
When things go wrong: contamination risk
Subsurface contamination from a poorly sited septic system affecting a bore or rainwater supply is a serious public and environmental health issue. In NSW, contaminating a water supply carries significant penalties under the Protection of the Environment Operations Act 1997. Beyond compliance, drinking contaminated water, even from a system that appears to be working, can cause gastroenteritis, hepatitis A, and other waterborne illnesses.
If you’re moving onto a rural property and are unsure whether the existing septic and water systems are properly separated, a professional septic inspection combined with water quality testing is a worthwhile investment before you start using the bore or tank water as drinking supply.
FAQs
Do I need separate approvals for a bore and a septic system?
Yes. Bores require a Water Access Licence and bore construction approval from WaterNSW. The septic or AWTS system requires an OSSM approval from PMHC. The two approval processes are separate, but PMHC’s OSSM assessment will consider the bore location as part of the site analysis.
Can I install a composting toilet to reduce the load on my septic system?
Composting toilets can handle the solid/blackwater waste stream, reducing hydraulic loading on your septic or greywater system. In NSW, composting toilets require PMHC approval as part of your OSSM system. They don’t eliminate the need for a greywater management system, as kitchen, bathroom, and laundry greywater still needs to be managed.
What if my bore is already too close to my septic system?
This is a situation that needs professional assessment. Depending on soil type, aquifer depth and the type of septic system, the actual risk may be low or high. A hydrogeological assessment can inform the risk level. Solutions range from decommissioning one source, relocating the absorption area, or upgrading to an AWTS producing higher-quality effluent. Contact a licensed septic contractor and discuss with PMHC’s environmental health team.
How do I know if my rural property is in the Hastings River catchment?
All of the Port Macquarie-Hastings LGA drains into the Hastings River system or coastal lagoons, you are in a sensitive catchment area. PMHC’s mapping tools and NSW Planning Portal can confirm your flood and environmental constraints.