The clock is ticking. As your building approaches the end of its Defects Liability Period (DLP)—usually 12 to 24 months after completion—the developer is preparing to hand over full responsibility to the owner or Body Corporate.
Once that date passes, any undiscovered defects become yourfinancial problem.
While most DLP inspections focus on visible issues like cracked paint or sticking doors, the most expensive liabilities are often hidden underground. Stormwater failure is a leading cause of major building defects in Australia, yet it is rarely checked during the final handover walk-through.
Here are the critical stormwater assets you must audit before your warranty expires.
1. The Underground Pipe Network (CCTV is Mandatory)
You cannot assess a drainage pipe from the surface. Construction debris, crushed pipes from heavy machinery, and disjointed rubber ring joints are common defects that won’t cause a blockage immediately—but will cause major subsidence or blockages years later.
The Audit: Commission a full CCTV Drain Camera Inspection of all main lines. We look for:
- Crushed or ovalled pipes: indicating poor backfilling during construction.
- Construction debris: concrete slurry, bricks, or timber left inside the line.
- Belly/Sag in the line: causing water to pool and sediment to build up.
2. The On-Site Detention (OSD) Tank
Your OSD tank is a massive concrete vessel designed to hold back floodwater. If it fails, you risk flooding your own basement or the neighbours properties.
The Audit:
- Debris Check: Is the tank clean? Builders frequently use OSD tanks as trash cans during construction. If not cleaned out, this trash will block the outlet during the first major storm.
- Orifice Plate Verification: Is the flow control plate actually there? Is it the correct size? Without this, your system is non-compliant with Council.
- Step Irons & Access: Are the safety steps corroded or loose? Is the access grate functionally accessible for future maintenance?
3. Basement Pump Systems
In a basement car park, your pumps are your only line of defence against flooding. If they were installed cheaply or incorrectly, they will fail when you need them most.
The Audit:
- Pump Specification: Do the installed pumps match the engineering design? We often find cheaper, lower-capacity pumps swapped in during construction.
- Float Switches: Are they set correctly? If they trigger too late, your car park floods.
- Guide Rails & Chains: Are the lifting chains stainless steel or cheap galvanised metal that is already rusting? Can the pumps actually be lifted out for service?
4. Gross Pollutant Traps (GPTs) & Filters
These devices protect the environment from oil and litter. They are also expensive to repair.
The Audit:
- Internal Components: Are the filter baskets and baffles actually installed? We have inspected sites where the concrete pit exists, but the expensive internal filtration units were never fitted.
- Filter Cartridges: Are the cartridges already blocked with construction dust and sediment? If so, the builder should replace them before handover, saving you thousands in immediate maintenance costs.
5. Surface Drainage & Grates
Water flow relies on gravity. If the surface levels are wrong, water will bypass the drains entirely.
The Audit:
- Flood Testing: We physically run water over the driveways and hardstands to ensure it flows into the pits, not away from them or into foyer entrances.
- Grate Quality: Are the grates bicycle-safe and heel-safe? Are they sitting flush, or do they rock and bang when cars drive over them?
Summary: A Small Cost for Massive Savings
A professional Stormwater DLP Audit typically costs a fraction of the price of a single pump replacement or pipe relining job.
Don’t let the builder walk away with your future maintenance budget. Get independent eyes on your assets before the contract closes.
Is your building’s warranty about to expire?
[Book a Pre-Handover Stormwater Audit] with Stormwater Services Australia. We find the defects others miss.
