SA Stormwater Regulations 2025: New Build Requirements & Mini-Basin Rules
building a new home in adelaide?
Building a new home in South Australia has become more complex in 2025, with stricter stormwater management requirements that are catching many homeowners off guard. If you're planning a new build, understanding these changes could save you thousands of dollars and prevent costly delays.
The "Mini-Basin" Revolution
Gone are the days when you could simply connect your downpipes to the kerb and call it done. Councils across SA now require new homes to act as "mini-basins" – essentially turning your property into a small-scale water management system. This means incorporating:
Retention systems to capture and store rainwater
Detention tanks to slow down water release during storms
Rain gardens to naturally filter stormwater
Permeable surfaces like grid pavers instead of solid concrete
Technical Requirements Getting Stricter
The Planning Code now demands:
Higher floor levels in flood-prone areas
Hydraulic sign-offs from qualified engineers
100mm diameter pipes (up from the previous 90mm standard) to handle increased storm intensity
Designated overflow paths to direct excess water safely to the street
Regular maintenance of tanks and orifice systems
What This Means for Your Build
Volume builders often provide a "stormwater allowance" that can escalate quickly, and their default drainage solutions are typically the cheapest option – basic PVC pipes to the kerb. This might not meet the new requirements, leaving you with unexpected upgrade costs.
The new approach follows the principle of "catch it, slow it, store it, prove it" – meaning you need to demonstrate your system works effectively before getting final approvals.
Smart Planning Strategies
To navigate these requirements successfully:
Involve a stormwater specialist early in your design process
Use combo tanks that serve both rainwater reuse and detention purposes
Plan for larger pipe systems (100mm minimum) to future-proof your investment
Implement WSUD landscaping from the start rather than retrofitting
Keep detailed documentation of all approvals and specifications
Summary
SA's 2025 stormwater requirements represent a fundamental shift towards treating every new home as part of the broader water management system. While this adds complexity and cost to your build, proper planning and professional guidance can ensure compliance without budget blowouts.
Ready to tackle your new build's stormwater requirements? At Stormwater Plus, we specialise in designing compliant, cost-effective drainage solutions for Adelaide homeowners. Our expert team understands the latest SA regulations and can help you navigate the complexities of modern stormwater management. Contact us today for a consultation and ensure your new build meets all requirements without breaking the budget.
