Granny Flat & Second Dwelling Septic Systems | Statewide Wastewater Queensland
Building a granny flat or secondary dwelling in Queensland?
You’ll need a compliant wastewater system — and Statewide Wastewater is the trusted expert for septic tank and HSTP installations for second dwellings across South East Queensland.
Why Septic or HSTP Systems Are Essential for Granny Flats / Second Dwellings.
With Queensland’s updated planning rules, granny flats and second dwellings can now be rented to non-family members — but most aren’t connected to town sewerage.
That means you’ll likely need a council-approved septic tank or Home Sewage Treatment Plant (HSTP) to meet health and plumbing regulations.
💡 If you’re building a granny flat on acreage, rural land, or an unsewered property, you’re legally required to install an approved wastewater system.
Avoid costly delays, rejections, or fines — we’ll design and install the right system for your site and handle all approvals.
Our Specialist Services for Granny Flats & Second Dwellings
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📍 Site inspections & soil testing
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📄 Council approvals & documentation
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💧 Custom-designed septic or HSTP system
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🛠 Fast, expert installation
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🧰 Servicing, repairs & system upgrades
Whether you’re in a rural area or suburban block, we tailor your system to suit the property, use, and council regulations
Servicing All of South East Queensland
Our fully licensed team installs and maintains granny flat / second dwelling wastewater systems across:
Why More Queenslanders Trust Statewide Wastewater for Second Dwellings
As demand grows for granny flats and secondary dwellings across Queensland, choosing the right wastewater solution has never been more important. Whether you're building on acreage in the Scenic Rim, expanding a family home in Moreton Bay, or developing a rental unit in Somerset, Statewide Wastewater ensures your system is council-approved, reliable, and tailored to your site.
With over a decade of experience, we help homeowners and builders stay compliant and avoid delays — from site assessment and approvals to complete septic or HSTP installation.
💬 One system. One team. One simple solution — no stress, just results.
Frequently Asked Questions: Granny Flat & Second Dwelling Wastewater Systems
❓ Do I need a separate septic system for my granny flat in Queensland?
Yes, most granny flats and second dwellings that aren’t connected to town sewer will require their own wastewater system — such as a septic tank or a Home Sewage Treatment Plant (HSTP). This is a key requirement for council approval and long-term compliance.
❓ What size HSTP is required for a second dwelling?
The required size depends on the number of bedrooms and occupants. Most second dwellings need a system suited for 2–4 people. Our team can help assess your site and recommend the right HSTP to meet your needs and council regulations.
❓ Can I install a septic tank if my property isn’t on town sewer?
Yes. If your property doesn’t have access to town sewer, you’ll need an approved on-site wastewater system. Statewide Wastewater provides complete design, supply, installation, and ongoing servicing across Queensland.
❓ Do I need council approval for a second dwelling septic or HSTP system?
Absolutely. Council approval is mandatory for all on-site wastewater systems. We manage the entire approval process for you — including soil testing, system design, and documentation — to ensure full compliance with local regulations.