Not every home in the Hunter region is connected to town sewerage. Properties on the rural-residential fringe of Lake Macquarie, in the semi-rural parts of Maitland, Raymond Terrace, and throughout the broader Hunter Valley often rely on on-site septic systems. Some properties also use bore water for irrigation and sometimes pool top-up. When either of these systems is present on a property where a pool is being removed, there are specific considerations that must be worked through before and during demolition. This guide covers both scenarios for Hunter homeowners.
Quick answer (BLUF)
Pool removal near a septic system requires verifying the location of the tank and absorption trench before any excavation, striking a septic tank or trench with an excavator is a biohazard and a costly repair. Near a bore, the concern is contamination of the bore casing and aquifer from pool chemicals, backfill material or disturbed soil. Both issues are manageable with proper planning.
Septic systems: the key risks
Separation distances: Most NSW septic system installation standards specify minimum separation distances between the septic tank and absorption trenches and other features:
- Absorption trenches must typically be at least 1.5m from property boundaries and at least 5m from any structure
- Separation from a swimming pool was not always formally specified in older installation records, so pools and septic systems can sometimes be in close proximity on older Hunter properties
What you’re protecting: The concern is not just breaking the tank or pipe (though that’s messy and expensive). The absorption trench system, the network of perforated pipes through which treated effluent disperses into the soil, can be damaged by the weight of excavators or by backfill that alters drainage patterns.
Finding your septic system: If you don’t have a site plan showing the septic layout, your local council may have records (particularly for systems installed post-1980). The Environmental Health Officer at Lake Macquarie City Council or Maitland City Council can often assist with historical records. Alternatively, a plumber with a drain camera or a septic service contractor can locate the tank and trace the trench line.
Practical approach: Mark the septic tank lid location and all visible inspection risers before demolition begins. The contractor works around these with appropriate standoff. If the trench system runs near the pool, hand-digging to locate the trench line before machine excavation in that area is advisable.
Draining the pool when you have no sewer connection
Properties on septic systems cannot drain pool water to the sewer (there is no sewer). Options for pool drainage on unsewered properties:
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Pump-out by truck: A liquid waste contractor (licensed in NSW) pumps the pool water into tankers and disposes of it at an approved facility. For a 50,000-80,000 litre pool, this involves multiple truck loads and costs $800 to $2,500 depending on the volume and distance.
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Discharge to land: Under Lake Macquarie City Council and other Hunter council requirements, dechlorinated pool water (chlorine below 0.5mg/L) can sometimes be discharged to a suitable vegetated area on the property via a slow-release approach, not as a flooding event. This requires council consultation and is only appropriate where the property has sufficient area to absorb the volume without waterlogging or runoff.
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Absorption pit: Some contractors create a temporary absorption pit (a deep trench filled with aggregate) to receive pool water slowly. This is acceptable in sandy soils common in parts of Lake Macquarie but problematic in clay soils where absorption is minimal.
Never discharge pool water directly to a septic system, the volume will overwhelm the system and the chlorine/salt content will damage the bacterial treatment process.
Bore water: the key risks
Many Hunter and Lake Macquarie rural-residential properties use bore water (groundwater extracted from a bore/well) for garden irrigation. Some also use it to top up the pool.
Contamination pathways during pool removal:
- Pool chemicals (chlorine, acid, algaecide residues) from the pool water or pool walls entering the soil and reaching the aquifer
- Disturbed soil and backfill material altering natural drainage patterns around the bore
- Damage to the bore casing if excavation occurs close to the bore
Clearances: NSW Department of Primary Industries - Water (now part of DPIE Water) guidelines specify minimum clearances from bores for certain works. As a general guide, significant excavation within 20-30m of a production bore should be discussed with your contractor and potentially with a groundwater consultant.
Practical approach: Know the location of your bore before demolition. Mark it clearly. Do not store chemicals, fuel or demolition waste near the bore. If backfill is being placed near a bore, use clean, certified fill material (not recycled material that could have contamination).
What to do if you hit a septic tank
If an excavator strikes a septic tank or breaches an absorption trench during pool removal, work stops immediately. The contractor is responsible for notifying the property owner, and a licensed plumber or septic specialist must attend to assess the damage. Repair costs for a struck concrete septic tank can run $2,000 to $8,000. This situation is avoided by proper pre-work planning, see above.
Rural-residential suburbs in the Hunter where this is most relevant
Properties in these areas are most likely to have septic systems and/or bores:
- Rural-residential parts of Lake Macquarie (Morisset and surrounds, Wyee, Wangi Wangi, Bonnells Bay)
- Rural-residential edges of Newcastle (Seaham, Heatherbrae surrounds)
- Maitland fringe and lower Hunter Valley rural-residential
- Lemon Tree Passage and Port Stephens area
- Some acreage properties in the Raymond Terrace hinterland
FAQs
My property is connected to town water but has a bore, do I still need to worry?
Yes. Having town water doesn’t affect bore water contamination risk during pool removal. If there is an active bore on the property, its location and the contractor’s activities near it need to be managed.
Does pool removal affect the function of my septic system?
Not if the work is kept clear of the tank and trench system. The pool’s removal eliminates the pool water discharge load, which can actually be a positive for properties where pool backwash was being directed into the septic system (an incorrect and potentially overloading practice).
Can I get a certified fill specifically for use near a bore or septic system?
Yes. Clean fill for use near water-sensitive areas should come with a supplier’s declaration of origin and a basic contamination test result. Your pool removal contractor should be able to source compliant clean fill materials for Hunter-region jobs.