Mosman NSW · 2026
Civil & stormwater CC package
Stormwater and surface drainage with a rainwater-reuse tank offsetting OSD, erosion and sediment control, and works-as-executed documentation.
On-site detention, drainage design and DA/CC stormwater documentation. Designed, documented, inspected and certified by one accountable team.
Hydraulic and structural, in one package. The stormwater management plan and OSD sizing are hydraulic (civil) work. The tank, basin or wall that holds the water is certified by a structural engineer. We do both, and issue the structural certification council needs.
Send your site plan and the council — a civil engineer replies with a clear scope and fee.
The stormwater management plan and on-site detention (OSD) sizing are designed by a hydraulic (civil) engineer. A structural engineer is needed separately to certify any concrete detention tank, basin or retaining wall that holds water.
Metric delivers the hydraulic stormwater design and the structural tank certification together — NSW-based, certification included. One brief, one program, one set of drawings that agree with each other.
Drainage, detention, driveways and site works: designed to AS/NZS 3500.3, Australian Rainfall and Runoff and your council's stormwater policy, documented to the conditions you've been given.
Drainage and on-site detention to AS 3500.3 and council policy: catchment plans, pipe and surface drainage, tank sizing, and rainwater-reuse storage where it can offset the detention volume.
Flood impact assessment and compliance statements for constrained lots, including overland-flow paths and swales where a consent condition calls for them.
Longitudinal sections, profiles and pavement design to AS 2890: vehicular crossings, parking layouts and hardstands, checked against AS/NZS 2890.1 for off-street parking.
Cut/fill strategy, batters and site retaining coordination, set out with the structural design rather than after it.
Council-compliant ESC plans, prepared to Managing Urban Stormwater: Soils & Construction (the Blue Book) and the controls your consent conditions name.
Designs resolved around sewer easements, services and authority assets, so the drainage line has somewhere legal to go.
Complete civil documentation coordinated with the structural set: the stormwater management plan, details and sections a DA or Construction Certificate submission needs.
Civil design for small-lot subdivisions and dual occupancies: drainage, levels and driveway design resolved lot by lot.
The trafficable slab and tank designed to AS 1170, AS 3600 and AS 3735 (with AS 5100 vehicle loading where required), and the structural certification council needs, issued with the hydraulic design.
The more of this you have, the tighter the fee. Missing most of it is not a problem; it just changes what we assume and what we exclude.
Every council sets its own stormwater policy, permissible site discharge and storage requirement. Tell us the council and we know which rules apply.
Whatever you have of the proposal — the architect's drawings, a site plan, or a builder's scope of works.
The stamped approved plans and the Notice of Determination (or the DA consent number). The conditions tell us exactly what has to be designed and certified.
Where you have it. It flags the planning constraints that sit over the lot.
Levels drive drainage. A current survey lets us design to real surface levels instead of assumed ones.
If you have one. Helpful for the tank and slab design; not required to quote.
Where a certifier has issued one, it is the definitive list of what still has to be cleared, and we price against it.
Including an earlier Metric design. If a set already exists, revising it is usually cheaper than starting again.
Don't have most of that yet? A sketch and the council name are enough to start. We'll tell you what else we need to price the job, or call 0404 344 027 and we'll talk it through.
A sample of the civil and stormwater packages behind builds across Greater Sydney and the NSW coast.
Stormwater and surface drainage with a rainwater-reuse tank offsetting OSD, erosion and sediment control, and works-as-executed documentation.
Driveway and parking civil design with stormwater catchment, OSD sizing and drainage layout for a commercial building.
Stormwater and civil CC documentation including an overland-flow swale, vehicular crossing detail and driveway longitudinal sections.
Stormwater management plan drawing set for a commercial building: siteworks and management plan, longitudinal section and catchment plan.
Full civil package for a mixed-use building over one basement: OSD, stormwater, car park and access road design.
Structural, civil and stormwater design with staged construction inspections through to completion.
Client names, addresses and drawings stay confidential: scope and suburb only.
Upload the site plan, DA conditions or a sketch, name the council, and tell us your timing.
A civil engineer reviews the site, confirms what the council and certifier require, and raises any questions.
You get a written scope and fixed fee within 24 hours on business days — no obligation.
On acceptance we design and document the works, attend the site inspections scoped in the proposal, and issue the certification listed.
Certifier chasing you for the stormwater? Call 0404 344 027.
Yes. Send what you have — architectural drawings, a site plan, a sketch, photos or the council's letter — and we'll tell you what we need to price the job. The council name and a site plan are enough to start.
The site address and council, what you're building, any drawings or the DA consent conditions you've been given, and your timing. A survey and a geotechnical report help but are not required to quote.
The proposal. You get a written scope and fixed fee within 24 hours on business days. The design program is set out in that proposal and agreed before we start.
The proposal itemises what is covered — the stormwater and civil design, calculations, drawings and the certification listed — with one design-development round and two revisions per item. Anything outside that, such as extra site visits or changes to the brief, is priced at the schedule of rates in the proposal and agreed before it's done.
Certification is by engineering design, calculation and visual site inspection — we don't do physical or material testing. Construction-stage inspections are scoped as an allowance (a stated number of visits) and listed in the proposal, so there are no surprises.
Often yes: the hydraulic design sizes the storage, and a structural engineer certifies the tank, slab or wall that holds it. We do both in one coordinated package, including trafficable tanks under driveways.
You'll see a reference number straight away. An engineer reviews the enquiry and comes back within 24 hours on business days with any questions and a fixed-fee proposal. Nothing is charged until you accept it.
No engineer can guarantee a council or certifier's decision. We design to AS/NZS 3500.3, Australian Rainfall and Runoff and your council's stormwater policy, document to the conditions you've been given, and respond to review comments on our work.
Plain-English notes on the questions owners, builders and architects ask us most.
Send the site plan and the council. A registered engineer comes back with a clear, fixed-fee proposal within 24 hours on business days.