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Sponge-city concept for combined rainwater reuse and detention

GRAF Australia

GRAF | REUSE guide

Rainwater reuse and detention

Combine usable reuse storage with controlled stormwater detention when the site needs both outcomes.

Request a project quoteCall 1300 131 971

In short

Combined rainwater reuse and detention serves sites that need usable water and peak-flow control. GRAF | REUSE Detention + Reuse System coordinates reuse storage volume, detention behaviour and a pump or PRESS package around catchment and demand. GRAF | LIFT, PRESS, REUSE and CARE are being rolled out Australia-wide excluding Victoria. Project delivery, commissioning and field attendance are confirmed against location and scope.

How it works

Catchment feeds storage that serves reuse demand while detention controls allowable discharge.
Commercial water reuse trainCollect and filter rainwater or suitable treated water, store it, treat where required, then pump and control delivery to approved reuse applications.CollectRoof / sourceFilterInlet protectionStoreGRAF tanksTreatIf requiredPumpPRESS / transferReuseApproved useGRAF | REUSE connects storage, treatment and pumping around the site duty

What to do next

  1. 01

    Separate the two duties on paper

    Reuse demand and permitted discharge rate are different design targets.

  2. 02

    Size combined or split volume

    Confirm how reuse storage and detention volume interact on the site.

  3. 03

    Add filtration, pumping and controls

    Filter inlet, PRESS or transfer package, and detention outlet arrangement.

Two objectives on one commercial site

Reuse wants reliable stored water for toilets, irrigation or washdown. Detention wants controlled outflow during storms. A combined package must respect both, including freeboard and outlet constraints.

Where the site only needs OSD, use stormwater detention guidance. Where it only needs non-potable supply, use the commercial rainwater reuse guide.

GRAF storage used for combined reuse and detention volume
Storage geometry must support both reuse draw-off and detention behaviour.

What the design must account for

Catchment, rainfall, reuse demand, required detention volume, allowable discharge, filtration, pump or PRESS package requirements, controls and site access.

Do not invent a single generic volume that claims to satisfy every council OSD rule and every reuse demand. Project data drives selection.

GRAF underground systems supporting dual water management objectives
Underground systems help constrained commercial footprints.

Compare options

Pick the package that matches the site objectives.

Site needGuide / packagePrimary outcome
Reuse onlyCommercial rainwater reuseNon-potable supply
Detention onlyOSD / stormwater detention guidePeak-flow control
BothDetention + reuse systemSupply + controlled discharge
Treated sourceTreated-water reuseQuality-led delivery

Specify these products

Frequently asked questions

Can one system provide rainwater reuse and detention?+
Yes. Some commercial sites need usable reuse storage and controlled stormwater detention on the same project. GRAF | REUSE Detention + Reuse System is the packaged pathway for that combined duty.
How is combined volume designed?+
Final design must account for catchment, rainfall, reuse demand, required detention volume and allowable discharge. Reuse and OSD objectives cannot be sized from one number alone.
Is this the same as a standard OSD tank?+
No. A pure OSD or detention system focuses on peak-flow control. A combined system also reserves or manages volume for reuse demand and pumping.
What pumping package is used?+
A pump or GRAF | PRESS package is selected around the reuse delivery duty, while detention outlets remain designed for the permitted discharge rate.
Is the combined package available in Victoria?+
GRAF | REUSE commercial packages are rolling out Australia-wide excluding Victoria. Confirm delivery against project location and scope.

Need combined reuse and detention sized?

Send catchment, demand and discharge limits. Call 1300 131 971 or use the quote form.

Request a quote