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BUILD YOUR DREAM HOME
Energy Efficient,
and built to last
Internal Drainage
Internal plumbing encompasses the network of water supply and sanitary drainage systems installed within the building envelope. It includes the design, installation, and maintenance of:
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Cold and hot water reticulation systems, including flow and pressure regulation devices
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Sanitary fixtures such as basins, sinks, toilets, showers, baths, and associated tapware
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Fixture branch drains and vents connected to the building’s sanitary drainage stack
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Hot water units, tempering valves, and associated pipework
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Floor wastes, gully traps, and overflows where applicable
All internal plumbing systems must comply with the Plumbing Code of Australia (PCA), AS/NZS 3500 series, and relevant local council or authority regulations. At GHP Plumbing & Civil, we specialise in compliant and efficient internal plumbing for residential and commercial projects, ensuring seamless integration with external drainage, roof plumbing and civil infrastructure.
Our work includes close coordination with builders and engineers to deliver systems that are fit-for-purpose, energy efficient, and built to last.
External Drainage
External drainage refers to the below-ground pipework and infrastructure responsible for safely conveying wastewater, stormwater and subsoil water away from a property to approved discharge points. This system plays a critical role in protecting structures, preventing flooding and ensuring environmental compliance.
At GHP Plumbing & Civil, we specialise in the design and installation of external drainage systems for residential and commercial projects, with services including:
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Sewer drainage: Installation of graded PVC or vitrified clay pipework, inspection shafts, boundary traps and connection to Sydney Water or local authority sewer infrastructure.
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Stormwater drainage: Construction of stormwater lines, charged systems, grated drains, pits, detention tanks, absorption trenches and connections to legal points of discharge.
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Subsoil drainage: Installation of ag drains and geotextile-wrapped pipe systems to relieve groundwater pressure and manage moisture around foundations and retaining structures.
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Site-specific solutions: Such as silt pits, gross pollutant traps, and on-site detention (OSD) systems for compliance with council stormwater management requirements.
All external drainage work is carried out in accordance with AS/NZS 3500, local council regulations, and where applicable, Sydney Water requirements. Our team is fully licensed and accredited to complete works on Sydney Water assets, including construction of sewer mains under the Major Works Accreditation Scheme.
With decades of experience and deep civil plumbing capability, GHP delivers efficient, compliant and long-lasting drainage solutions tailored to each site’s needs.
Rough-In
Plumbing rough-in is the critical pre-wall stage of construction where all water supply and drainage pipework is laid out within the structure, prior to plastering, cladding, or tiling. This phase ensures that all plumbing infrastructure is properly positioned, connected and pressure-tested to support the final fit-off of fixtures and appliances.
At GHP Plumbing & Civil, our rough-in services include:
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Cold and hot water pipework layout, installed within wall frames, floors and ceilings to designated fixture locations
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Sanitary drainage pipework from fixtures to stacks or under-slab lines, including venting systems for compliance with AS/NZS 3500
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Stormwater provisions, where applicable, for balconies, internal gutters or integrated roof systems
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Allowance for mechanical services such as water feeds to heating/cooling units, refrigeration, or fire services
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Coordination with electricians, HVAC, and framing teams to prevent clashes and maintain project timelines
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Pressure and water testing to verify system integrity prior to wall closure
Rough-in plumbing must be highly accurate, as any deviations can result in delays or costly rework during fit-off. All installations are completed in accordance with the Plumbing Code of Australia, relevant local authority standards and manufacturer specifications.
With five decades of experience, GHP Plumbing & Civil works closely with site supervisors and construction teams to deliver rough-ins that are neat, code-compliant and ready for seamless final fit-off.
Downpipe Installation
Downpipes are a critical component of a building’s roof drainage system, designed to direct rainwater from gutters to the stormwater drainage network or approved discharge points. Proper installation is essential to prevent water ingress, structural damage and to maintain compliance with hydraulic design requirements.
At GHP Plumbing & Civil, we provide professional downpipe installation for residential, commercial, and industrial projects, ensuring full compliance with AS/NZS 3500.3 – Stormwater Drainage, and the Plumbing Code of Australia.
Our downpipe installation services include:
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Correct sizing and spacing based on roof catchment areas, rainfall intensity and system layout
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Connection to gutter outlets with appropriate fittings (e.g., pops, nozzles, rain heads) for effective water capture
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Vertical alignment and support using compliant brackets and fixings, maintaining expansion allowances where required
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Termination options including:
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Direct connection to stormwater systems
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Charged line systems
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Rainwater tanks (including first-flush devices and leaf diverters)
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Ground-level dispersion or soakwell systems, as permitted by local authority
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Non-corrosive material selection to suit the building’s design and environmental conditions – including PVC, Colorbond, copper or stainless steel
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Sealing and weatherproofing at all entry points to prevent leaks and building damage
We also work closely with project engineers and builders to ensure integration with OSD (On-Site Detention) systems, subsoil drainage and other hydraulic elements.
With decades of expertise in roofing and drainage interface systems, GHP Plumbing & Civil guarantees durable, code-compliant, and aesthetically integrated downpipe installations tailored to your project's needs.
Fit-Off
The plumbing fit-off is the final stage of the plumbing installation process, where all visible fixtures, tapware, appliances, and fittings are installed and connected to the rough-in plumbing systems completed earlier in the build. This stage is critical in ensuring the system functions correctly, looks professional, and complies with all relevant codes and standards.
At GHP Plumbing & Civil, our plumbing fit-off services include:
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Installation of sanitary fixtures: Toilets, basins, baths, showers, urinals, sinks, and laundry tubs
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Tapware and mixers: Wall and bench-mounted taps, shower mixers, bath outlets, and filtered water taps
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Kitchen and laundry connections: Dishwashers, washing machines, boiling/chilled water units, and instant hot water systems
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Water heating systems: Final connections and commissioning of gas, electric, or solar hot water units
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Final stormwater and sewer connections: Gully risers, overflow relief gullies (ORGs), and grated surface fittings
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System testing and commissioning: Ensuring all fixtures are operational, correctly connected, and leak-free
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Compliance certification: Submission of final inspection reports and compliance certificates as required by local authorities
All fit-off works are completed in accordance with AS/NZS 3500, the Plumbing Code of Australia, and manufacturer installation guidelines. Clean presentation, accurate alignment and durable sealing are hallmarks of our fit-off workmanship.
With decades of experience across residential and commercial projects, GHP Plumbing & Civil ensures every fit-off is delivered with precision, professionalism and attention to detail, ready for handover or occupancy.