A STORM assessment requires enough project information to measure the site, identify its runoff-generating surfaces and model the stormwater treatment measures proposed for the development.
The assessment can usually begin once current architectural plans show the site boundary, building roofs, driveways, paving, landscaping and the proposed location of any stormwater treatment measures.
The assessor will generally need:
The drawings do not always need to be fully resolved before work begins. However, the assessment should be reviewed when later changes affect the measured areas, runoff connections or treatment strategy.
A STORM assessment translates the physical design shown on the project drawings into a quantitative stormwater treatment model.
To do this accurately, the assessor needs to understand:
Not every detail needs to be final at the start. The plans must nevertheless contain enough information to support a realistic treatment strategy.
For a broader explanation of STORM reports and Victorian treatment assessments, visit the Certified Energy STORM Knowledge Hub.
The initial information should identify the property and the type of development proposed.
This commonly includes:
This context helps establish the likely assessment boundary and allows the report to be tied to the correct project and drawing set.
The site plan is usually the most important drawing for a STORM assessment.
It should show, as far as available:
A dimensioned plan or scaled PDF is preferable because it allows the various surface areas to be measured accurately.
Where only an image or unscaled concept plan is available, additional dimensions or area schedules may be needed.
The roof plan helps establish the roof catchments available for rainwater harvesting.
It can also reveal whether different parts of the roof are likely to drain in separate directions.
Useful roof information includes:
The complete roof area should not automatically be assigned to one tank. Only roof sections that can realistically drain to that tank should be included as connected catchment.
The assessment needs a clearly defined total area against which the individual surface types can be checked.
This will commonly be the title area or another project boundary established for the assessment.
The total should reconcile with the sum of:
Where the sum of the entered surfaces differs materially from the total site area, the assessment may contain an omission, overlap or classification error.
Impervious areas generate most of the runoff evaluated in a STORM assessment.
The assessor will generally need to identify:
Small surfaces should not be ignored simply because they are individually minor. Collectively, paths, porches and other paved areas can affect the overall treatment result.
The assessment also needs to distinguish surfaces that remain pervious or form part of the proposed treatment response.
Relevant information may include:
The classification should reflect the actual proposed construction.
Conventional concrete or tightly jointed paving should not be counted as permeable solely because it is located outdoors.
Where rainwater harvesting forms part of the treatment strategy, the assessor needs the proposed storage capacity of each tank.
The information should identify:
If the tank size has not been selected, the assessment can test practical alternatives. The final nominated capacity should then be carried into the architectural and hydraulic documentation.
Tank capacity alone is not enough to model rainwater harvesting.
The assessor must also know how much roof runoff reaches each tank.
For a multi-dwelling project, this may require a schedule such as:
Where the exact downpipe arrangement is not yet designed, a reasonable preliminary catchment can be tested. It should still be physically achievable based on the roof form and proposed tank location.
The assessor needs to understand how stored rainwater will be drawn from the tank.
Possible reuse demands may include:
For residential projects, it is also useful to confirm:
Reuse assumptions should represent the system that will actually be constructed. They should not be added to the model without corresponding design commitments.
Where a raingarden is proposed, the assessment needs enough information to represent its treatment area and connected runoff catchment.
Useful details include:
Raingardens are designed to filter runoff using vegetation, soil and biological treatment processes. The treatment area used in the model must therefore correspond with a real and buildable part of the site. :contentReference[oaicite:1]{index=1}
If permeable paving contributes to the treatment result, the assessor will need to know:
A general note stating “permeable paving where possible” is usually not enough to establish a measurable treatment area.
The assessment does not necessarily require a complete hydraulic design, but it does need a credible understanding of where runoff goes.
Helpful information may include:
Where these details are not yet designed, the assessor may identify assumptions that need to be confirmed during later hydraulic or civil coordination.
Council correspondence can be as important as the drawings because it helps clarify why the assessment is being requested.
Relevant documents may include:
The wording can help determine whether council expects a focused treatment assessment or a broader package that also addresses drainage, detention, discharge or maintenance.
Depending on the project, it can also be useful to provide:
This material helps place the assessment within the correct planning context without turning the STORM report into a broad planning or sustainability document.
A landscape plan is particularly useful where the treatment strategy includes:
The plan helps confirm that sufficient physical space remains available and that the modelled treatment areas do not conflict with access, services, tree planting or private open space.
If the landscape plan has not yet been prepared, the architectural drawings should at least reserve the required treatment area.
Detailed hydraulic or civil drawings are not always required before a STORM assessment can begin.
Where available, they may help confirm:
The presence of this information improves coordination but does not make every hydraulic calculation part of the STORM assessment itself.
Yes. A preliminary assessment can often begin from developed concept plans.
This can be beneficial because it allows the project team to test:
An early assessment should be treated as preliminary where major design elements remain unresolved.
The result should be reviewed after changes to:
Missing information does not always prevent the assessment from starting.
Where appropriate, a preliminary model may use clearly stated assumptions for matters such as:
These assumptions should be identified for the project team and confirmed before the assessment is finalised.
The final report should not quietly rely on unverified measures that are absent from the design documentation.
Several recurring issues can delay or weaken an assessment:
Providing the current drawing set and the exact council request at the outset usually reduces unnecessary revisions.
A focused stormwater treatment assessment does not normally require every aspect of the final construction package before modelling can begin.
Depending on the project, the initial assessment may not need:
Some of these items may still be required elsewhere in the planning, drainage or construction process.
The STORM assessment needs sufficient information to model treatment performance; it does not replace the separate design of every stormwater component.
Project correspondence may refer to a STORM assessment even where the current accepted output uses a newer assessment platform.
Before finalising the submission, it is useful to confirm:
Current planning requirements can extend beyond treatment performance to retention, detention, discharge and the wider stormwater management system. The exact submission scope should therefore be read from the applicable planning controls and council request. :contentReference[oaicite:2]{index=2}
Before sending a project for assessment, check whether the following items are available:
Where an item is not yet available, it can be identified as a design input requiring confirmation rather than delaying all preliminary assessment work.
Certified Energy can review the available plans and identify whether there is enough information to begin a stormwater treatment assessment.
The process may include:
The assessment can often begin before every construction detail is final, provided the project team understands which assumptions must be retained or confirmed.
Explore the STORM Assessment Knowledge Hub or send through the current plans and council correspondence for an initial project review.
The assessment generally needs current plans, the total site area, impervious and landscaped surface areas, proposed stormwater treatment measures, rainwater tank information and relevant council correspondence.
A site plan and roof plan are usually the most important. Floor plans, elevations, landscape plans and available hydraulic or civil plans may also assist.
No. A preliminary assessment can often begin from developed concept plans, but the result should be checked again if the design changes.
It is highly useful because it helps measure roof catchments and determine which areas can realistically connect to each rainwater tank.
The assessor generally needs the tank capacity, connected roof area, uses or dwellings served and proposed reuse demands.
Not always. The assessment may begin before detailed hydraulic design where the proposed catchments, treatment measures and reuse strategy are sufficiently clear.
Yes. Council correspondence can clarify whether a focused treatment assessment, broader stormwater documentation or a particular modelling method is expected.
Practical tank options can be tested during a preliminary assessment. The selected capacity should then be incorporated consistently into the project documents.
Reasonable preliminary assumptions may be used where details remain unresolved, but they should be clearly identified and confirmed before the final report is issued.
Not ordinarily for the treatment assessment itself. Drainage capacity, detention, discharge and flood matters may need separate specialist documentation.