Concrete pools are the most common type found in established Southern Highlands properties. Whether gunite-sprayed or shotcrete construction, pebblecrete or rendered finish, these pools share the same basic structure: a steel-reinforced concrete shell, typically 200-300mm thick, set into a ground excavation. They’re durable, repairable in theory, but increasingly expensive to maintain as they age, and ultimately, when the decision is made to remove them, the demolition process is more involved than for fibreglass or above-ground pools.
This guide walks through exactly what happens during a concrete pool removal in the Southern Highlands, from the first machine arriving on site to the final compaction inspection.
Quick Answer (BLUF)
Concrete pool removal involves: draining the pool, removing fencing and surrounds, hydraulically breaking the shell in sections, excavating and sorting the rubble (crushed material used as sub-base, excess carted away), disconnecting and capping all plumbing, backfilling the excavation in compacted layers, and obtaining a compliance sign-off from your certifier. The whole process typically takes two to four days on site, with council approval arranged beforehand.
Stage 1: Pre-Site Preparation (Days Before)
Before any machinery arrives, several things need to be in order:
Council approval issued. Your Complying Development Certificate (CDC) or Development Application (DA) consent must be in hand before work starts. This is a legal requirement. If your contractor is managing the approval, confirm the certificate has been issued and note the reference number.
Pool drained. Most pools are either drained before arrival or the crew drains the pool on day one. Water must be discharged appropriately, to the sewer via the property’s plumbing system, not to the stormwater system or neighbouring land. If the pool has been sitting stagnant (green water), chlorination before discharge may be required.
Access cleared. The site should have clear access for at least one tracked excavator (typically needing a gate opening of 1.2-1.5m minimum) and at least one tipper truck. Overhanging branches, stored items and vehicle obstructions should be removed.
NSW Dial Before You Dig. Your contractor will have submitted a request through Dial Before You Dig to confirm the location of any underground services, gas, water, electricity, in the pool area. This is mandatory.
Stage 2: Fencing, Coping and Surrounds Removal
Day one typically begins with removal of all pool fencing, coping stones, surrounding concrete or paving, and any pool equipment (pump, filter, heater). The pool fence posts are pulled or cut at ground level; electrical connections to pool lights and equipment are isolated at the switchboard.
The pool equipment (pump, filter, chlorinator) can often be sold secondhand if it’s in reasonable condition. Your contractor may offer to handle this, or you can choose to sell it before the job.
Stage 3: Shell Demolition
With the surrounds clear, the excavator positions alongside the pool and begins breaking the shell. A standard tracked excavator with a hydraulic breaker attachment (rock hammer) is the primary tool for concrete pool demolition.
The hydraulic breaker drives repeated rapid impacts into the concrete shell, fracturing it progressively. Starting at one end, the operator works along the shell, breaking the walls down into the pool floor, then breaking the floor itself. The steel reinforcing (rebar) within the shell is exposed as the concrete fractures, the rebar is cut with hydraulic shears or angle grinders and separated from the concrete rubble.
Why rebar separation matters: Steel rebar cannot remain in the backfill material, it will corrode over time, creating voids and potential ground instability. All rebar must be separated and removed from site for recycling as scrap metal.
The concrete rubble is sorted:
- Smaller crushed concrete fragments (under 50-75mm) are suitable for use as sub-base material within the backfill
- Larger lumps and any contaminated material are loaded for disposal
- Steel rebar is bundled separately for scrap metal recycling
For the Southern Highlands specifically, old pebblecrete surfaces sometimes contain silica that requires careful handling, proper dust suppression during breaking is required.
Stage 4: Plumbing Disconnection
During or after shell demolition, all plumbing connections are addressed:
- Inlet and return lines running through the pool walls are cut back and capped with appropriate plugs or end caps
- Main drain (at the pool floor) is capped
- Hydrostatic relief valve (if present), designed to relieve groundwater pressure, must be removed and the opening properly sealed
- Backwash line is cut and capped
- Equipment connections are disconnected at the equipment pad
Leaving plumbing open underground creates drainage channels that can direct groundwater to unintended locations and cause soil erosion within the backfill. Proper capping is a compliance requirement, not optional.
Stage 5: Backfilling and Compaction
The backfill stage is as important as the demolition stage, and it’s where shortcuts are most tempting and most consequential.
The Highlands challenge: Clay soils around Bowral and Mittagong are prone to shrink-swell movement. Basalt soils in Robertson and Burrawang have large angular particles that create voids. Both soil types require more careful backfill management than the sandy loam soils of coastal areas. See our soil compaction and settlement guide.
Backfill methodology:
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Drainage layer. A 200-300mm layer of clean 20mm drainage aggregate is placed at the base of the excavation. A geotextile fabric is placed on top of this layer to prevent fine soil from migrating down.
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First fill layer. Crushed concrete rubble and imported select fill are placed in a 300mm layer and compacted with a vibrating plate compactor or small roller. The compaction equipment must reach all areas of the excavation.
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Subsequent layers. Additional 300mm layers are added and compacted in turn until the excavation is filled to near natural surface level.
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Top layer. A 150-200mm layer of clean topsoil or imported garden mix is placed at the surface to support future landscaping.
Compaction testing: Your certifier may require a compaction test (typically a nuclear density test or dynamic cone penetrometer test) at one or more stages during backfill. The test confirms that compaction meets the specified standard, which protects you against future subsidence claims and satisfies the certification requirements.
Stage 6: Site Tidy and Certifier Inspection
Once backfilling is complete:
- All waste material, scrap steel and equipment is loaded and removed from site
- The site is raked level and left in a tidy state
- Sediment and erosion control measures are removed (or left in place as required by approval conditions)
The certifier then conducts a final inspection, reviews the compaction records, and issues the Compliance Certificate confirming the work was completed in accordance with the approval.
Stage 7: Post-Removal Administration
After the physical work is done, two administrative steps remain:
- Update the NSW Swimming Pools Register. The pool must be deregistered or the registration updated to reflect removal. This is a legal requirement.
- Keep the documentation. The CDC, compliance certificate, backfill compaction records and disposal dockets should be retained with your property records. You’ll need them if you sell, subdivide or build over the area.
Our pool removal process timeline guide covers the full timeline from first quote to final sign-off.
FAQs
How long does a concrete pool removal take?
A typical residential concrete pool in the Southern Highlands takes two to four days on site. Small pools on accessible sites in Bowral or Mittagong may be completed in two days. Large pools, rocky sites (Robertson, Burrawang), or properties with access challenges may take three to four days or longer. Council approval is arranged beforehand, this takes two to four weeks.
Can the old concrete be left in the ground?
Not in its shell form, a hollow or partially intact concrete shell underground is a structural hazard that will collapse over time, creating an unsafe void. The correct approach is to break the shell thoroughly and use the rubble (properly compacted) as part of the backfill. Some old practices involved punching holes in the bottom and leaving the shell in place, this is no longer considered acceptable practice and doesn’t comply with current standards.
What happens to the old pool plumbing that runs to the equipment area?
Plumbing connecting the pool to the equipment area (pump, filter) runs underground. It is cut and capped at the pool end. The section from the cap to the equipment area can either be left (capped and inert) or excavated and removed, depending on its routing and whether it’s in a future building or landscaping area.
Do I need to test the backfill compaction?
Your certifier will advise whether compaction testing is required as a condition of the CDC or DA. For larger pools or sites where future structures are planned, testing is standard. For smaller removals, visual inspection and compaction records from the contractor may be sufficient. Ask your certifier at the approval stage.