What is a Stormwater Engineer?

A Stormwater Engineer is a civil engineering specialist who assesses your site’s water runoff conditions and designs a stormwater drainage system that complies with council, BASIX, and building code requirements. This includes everything from roof runoff calculations to underground pipe layouts, detention tanks, and overflow discharge points.



This task happens during the early design and compliance stage, well before slab works commence.

What does a Stormwater Engineer do?

Typically, they will

  • Review your site survey, contours, and architectural plans
  • Calculate stormwater runoff volumes based on roof and hard surface areas
  • Design a compliant drainage system (e.g., OSD, pipes, tanks, overland flow paths)
  • Deliver a formal Stormwater System Assessment and Stormwater Design report
  • Liaise with your architect or council if requested


Some engineers also assist with council lodgement or stormwater compliance sign-off.

Barry's Toolbox

Don’t pour your slab until your stormwater plan is finalised — it affects downpipe locations, tank positions, overflow lines, and landscaping gradients.


And if your council requires an Onsite Detention (OSD) system, your stormwater engineer is the one who designs it — not your plumber.

What Makes a Stormwater Engineer?

Look for someone who:

  • Are experienced in residential site drainage and council submission processes
  • Understand your local authority’s requirements for OSD, kerb outlets, and flow paths
  • Provide clear hydraulic plans and accompanying calculations
  • Can adjust designs quickly if your site or DA changes
  • Communicate well with your certifier

Before You Begin: What You’ll Need Ready

To get quotes from Stormwater Engineers, you’ll need:

  • A site survey with levels and property boundaries
  • Architectural site plan and elevations
  • DA consent (if applicable) and any council stormwater conditions
  • Information about site classification or soil type
  • Preference for OSD vs non-OSD (if known)

Average Timeframe

For this task, Pros typically provide quotes within 3–5 business days.

When Can I Expect Quotes?

Timeframes often vary based on demand and the type of Pro you're engaging (e.g. a plumber). If additional communication or clarification is needed is needed, the quoting process may take longer.

 

Don't be alarmed if you don't receive quotes or communication from any Build Buddy Pros straight away. Some work is more complex and the Pro may need time to comprehend your documents or scope of work. Depending on the job, there may even be some work required by the Pro before they are able to quote (e.g. a site visit might be required).

 

If the average timeframe indicated here has passed, and you have not received any messages or quotes, please feel free to contact the Build Buddy Expert Guidance and Support team for an update on quoting for this task.

Frequently Asked Questions

  • Is stormwater design required for all builds?

    In most council areas, yes — particularly for new dwellings, duplexes, or major renovations. It’s essential if you’re discharging to street kerbs or public infrastructure.

  • What’s OSD?

    On-site stormwater detention (OSD) temporarily holds stormwater runoff on your property before releasing it at a controlled rate. It may be a tank, pit, or absorption trench.

How to Complete this Task?

STEP 1

Review and Adjust the Scope of Works

Timeframes may vary based on demand and the type of Pro you're engaging (e.g., a plumber). If additional communication or clarification is needed, the quoting process may take longer.

STEP 2

Confirm Required Documents Are Uploaded

Check that the following required document(s) are uploaded for this task. These are essential to proceed:

STEP 3

Update the Quality Assurance Checklist

Go to the Quality Assurance tab in this task and review the checklist. Edit any details to suit your project requirements. Being clear and upfront helps set expectations with the Pro. Updating the checklist before requesting quotes ensures everyone is aligned.

STEP 4

Request Quotes

Click the orange ‘Request Quotes’ button to start the quoting process.

STEP 5

Review the Quotes

Once you receive quotes:

  • Review each one carefully, including the payment schedule and any special terms
  • Download attached quote documents for detailed review
  • Check each Pro’s profile and read past client reviews

STEP 6

Communicate with the Pro

If needed, message or call the Pro to clarify details or negotiate terms.

STEP 7

Accept a Quote

Choose the quote that best suits your needs. Once you accept a quote, any other pending quotes will be automatically declined. An agreement will automatically be generated.

STEP 8

Complete the Tasks In Your App

New tasks will appear to guide you through this job — follow each step carefully. Make sure to use the Quality Assurance Checklist, and refer to your contract and final Scope of Works whenever needed.

NEED HELP?

Reach Out to Your Build Buddy Pro

If you have any questions or need a hand, your Build Buddy Pro is your best first contact. They’re a licensed expert in their field and can understand the ins and outs of your project. You can message them via the platform, or you can call them directly.


If you have already contacted your Build Buddy Pro and still need further assistance, the Build Buddy Expert Guidance and Support team are here to help. They will be able to guide you on your next steps or help you find answers to any questions you may have.