Stormwater - Frequently Asked Questions
Common Stormwater questions and terms explained.
What is the legal point of discharge? (Where can the water go?)
The legal point of discharge is the location approved by Council where stormwater from your property may be discharged. This could be:
Kerb and gutter in the street
A Council stormwater pipe
A Council drainage pit
Another approved drainage system
Identifying the legal point of discharge is often the most important step in the entire stormwater design process.
What Happens if My Property Falls Towards the Street? (High side)
Properties that fall towards the street are generally the simplest to service. Stormwater can often be collected and discharged by gravity to Council's kerb and gutter system or other approved drainage infrastructure.
What Happens if My Property Falls Away From the Street? (Low side)
Properties that fall away from the street can be more challenging. In these situations, Council will often require investigation of whether stormwater can be discharged by gravity to a downstream Council drainage system. This may involve obtaining a drainage easement through neighbouring properties to reach:
A Council stormwater pipe
A drainage pit
Kerb and gutter
Another lawful point of discharge
For many sites, obtaining a drainage easement is the preferred solution.
What is a Drainage Easement?
A drainage easement is a legal right allowing stormwater pipes to pass through another property. Although easements can involve additional time and cost, they often provide the most reliable long-term drainage solution and are frequently preferred by Council.
Neighbours are often reluctant to accept easements on their title and commonly refuse to. If this happens to you, a letter confirming the refusal is required from the neighbour. This enables your Engineer to pursue other alternatives for you.
How Much Does a Stormwater Management System Cost?
Unfortunately, there is no simple answer to this question.
Every site has unique characteristics, including slope, available drainage infrastructure, ground conditions, access constraints and Council requirements. As a result, stormwater solutions are typically customised for each property. Once a Stormwater Management Plan has been prepared, a qualified plumber or drainage contractor can inspect the site and provide a quotation based on the approved design and site conditions. As a general guide:
Item Typical Cost Range*
Minor compliance works (gutters, downpipes, pits and pipes) Approx. $2,000 - $8,000
Rainwater tank installation Approx. $2,000 - $10,000+
On-Site Detention (OSD) systems Approx. $5,000 - $30,000+
Drainage easements Highly site-specific
*Indicative costs only. Actual costs vary significantly depending on site conditions, access, excavation requirements, retaining walls, easement requirements and Council conditions.
For many properties, the most significant cost is not the pipework itself but establishing a lawful point of discharge. Properties that fall away from the street may require investigation of drainage easements, additional excavation, retaining wall penetrations or other specialised works.
In some cases, the cost of obtaining a drainage easement can exceed the cost of the stormwater pipework itself. Surveying, legal documentation, registration costs, negotiations with neighbouring property owners and downstream drainage works can all contribute significantly to the overall project cost.
Obtaining engineering advice early in the design process can help identify potential issues, establish a realistic budget and avoid unexpected costs later.