What is an OSD tank? On-site detention meaning and product options

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 a stormwater detention tank brief, not a rainwater reuse tank.

What an OSD tank is (and is not)

OSD means on-site detention: hold peak runoff on the lot, then discharge slowly to the street or waterway. Searchers often type osd tank, detention tank or stormwater detention tank for the same brief.

Rainwater tanks store water for reuse (irrigation, toilets, laundry). If the consent says harvesting or reuse, start with Carat or Platin underground rainwater packages instead of detention products.

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. For a criteria-only compare with concrete OSD tanks, see the EcoBloc vs concrete guide. GRAF Australia can also 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.

FAQ

What is an OSD tank?+

An on-site detention tank temporarily stores stormwater and releases it at a controlled rate to meet council peak-flow limits.

What does OSD tank mean?+

OSD tank means on-site detention tank: hold peak runoff on the lot, then discharge slowly. Same brief as detention tank or stormwater detention tank in most Australian searches.

Is an OSD tank the same as a rainwater tank?+

No. OSD / detention controls peak discharge. Rainwater tanks store water for reuse. Confirm the planning condition before you lock a product family.

What are detention tanks?+

Detention tanks are OSD vessels or modular systems that hold stormwater and release it slowly. GRAF options include EcoBloc crates and Carat / Platin detention tanks.

EcoBloc or a stormwater detention tank?+

EcoBloc suits modular inspectable volume under pavement. Carat / Platin detention tanks suit vessel-style OSD briefs. Hybrid sites exist.

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Need a GRAF Australia quote?

Call 1300 131 971 or send site details for sizing and supply.

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