GRAF Australia
Blog · 2026-03-26
What is an OSD tank in Australia?
An OSD tank (on-site detention) temporarily stores stormwater runoff and releases it at a controlled rate so developments meet council peak-flow limits. It is not a rainwater reuse tank.
Why councils require OSD
New roofs, car parks and hardstand increase peak runoff. OSD policies hold that volume on site and discharge slowly so downstream pipes and waterways are not overloaded.
Consent wording may say OSD, detention, attenuation, retention or rainwater reuse. Wrong product selection usually starts by misreading that condition.
EcoBloc crates vs detention tanks
EcoBloc builds modular underground volume under pavement or landscape, with inspectable options for maintenance. Carat and Platin detention tanks suit vessel-style briefs.
Choice depends on footprint, cover depth, load class and access. GRAF Australia can compare EcoBloc and detention tanks against your civil brief.
How to get a quote
Your engineer sizes volume from catchment, rainfall and permitted discharge against the local OSD policy. Use the GRAF Australia OSD design tool for a first pass, then send plans and location to grafaustralia.com.au or call 1300 131 971.
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Need a GRAF Australia quote?
Call 1300 131 971 or send site details for sizing and supply.