Stormwater downpipes from roof into stormwater drainage system brisbane

When it comes to stormwater drainage, Brisbane can be a tricky place to get it right. For example, plenty of homes in inner city suburbs have no stormwater access on their block. However, all properties must now connect to a ‘lawful point of discharge’ such as an authorised council stormwater drain or road. But what if your stormwater access point is on your neighbour’s land? Well, then you’re talking about an easement.

Sound complicated enough yet? Want to outsource it to the experts?

The Salmon Plumbing team are the drainage plumbers Brisbane trusts to keep them safe this storm season. We can help you develop and install an effective roofwater drainage system for your home. Here’s what you need to know when planning your stormwater drainage project.

Why stormwater drainage in Brisbane is crucial

We live in a sub-tropical environment, and that means plenty of rain. If you have an inadequate plumbing system in place, any downpour can lead to a potential disaster for your property. Brisbane’s history of flooding exacerbates this risk. The 2022 Queensland floods brought intense, record-breaking rainfall that quickly inundated homes, leaving an estimated damage bill of $2.22 billion.

The quicker you can remove excess water from your property, the lower your risk of long-term water damage to your home. Ideally, your stormwater drainage system should remove rainwater from your roof, gutters, and garden so that it is directed into stormwater drains, or other appropriate outlets or storage areas.

The environmental impacts of poorly managed stormwater drainage can be really serious, too. In Australia, the stormwater system is separate from the sewer system. While raw sewage is treated before it ends up in our waterways, stormwater typically isn’t. All manner of pollutants can end up in our rivers and oceans including soil and other organic matter, garden fertilisers, and even the car oil residue that washes off your driveway.

What happens if roofwater drainage is inadequate?

As a result of Brisbane’s climate and topography, issues with stormwater runoff can be a common problem for residents. Flood prevention means looking beyond your property line. If you don’t get your stormwater drainage sorted, you’re unlikely to be popular with the neighbours or your local council!

Some of the serious problems we see caused by poor rainwater drainage design include:

  • Damage to roof structures, timbers and other building materials
  • Issues with attracting unwanted termites
  • Flooding to areas around the home and into neighbouring properties
  • Erosion under slabs, foundations and gardens

Who should carry out a major stormwater drainage project?

Whether you’re building a new home or having stormwater drainage issues at an existing dwelling, your first step should be to engage a licensed plumber to review your block. It’s a plumber’s job to design a stormwater drainage system for your home that prevents flooding and stops contaminants from entering stormwater catchment systems.

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What’s considered when designing a stormwater drainage system?

When designing an effective stormwater system for your Brisbane property, your plumber will consider a range of important factors.

Water Sources

Stormwater can be collected from several sources:

  • Roofwater: Your roof size, the level of rainfall in your region, and the size of your gutter/downpipes are all factors that affect how roofwater needs to be managed.
  • Surface water: This is water that travels over your entire block. To manage surface water, the specific types of surfaces and the contour and fall of the ground surface need to be considered.

Your home’s flood risk

Brisbane stormwater drainage plans must consider the flood risk that comes with life in a sub-tropical climate.

The Queensland Government has developed the Floodcheck interactive map that lets you view historic floodlines, the likely extent of floodplains, and other relevant flood data and technical reports. You can search by address, lot/plan, town, and local government areas.

Water conservation and harvesting

When developing a stormwater drainage system, it makes sense to consider how roofwater can be harvested for use on your property. By installing a system that utilises roofwater for watering the garden, you are likely to notice a decrease in your water bills, too. If your rainwater tank installation is over ten years old, ask Salmon, the plumbers Brisbane trust, to check it over, and if necessary upgrade your old rainwater tank in time for storm season.

Council approvals

The Brisbane City Council does not maintain private stormwater lines. This includes your home’s connection to the kerb and channel via a kerb adaptor or the connection to an existing council stormwater pipe or manhole.

For houses built after 1975, the council requires stormwater to be managed in an approved manner (e.g. directed to council stormwater mains, kerb and channel). You’ll need to submit an application/notice to work on council property to connect stormwater or roofwater pipes from a residential or commercial development to any of the following:

  • kerb and channel
  • open drain
  • swale
  • enclosed drainage
  • stormwater gully
  • culvert

Council stormwater drainage infrastructure may be in the street, on private property, or in dedicated drainage easements. You can purchase copies of the Brisbane City Council’s stormwater drainage plans to assist with the development of your system. However, this is another resource a licensed and experienced plumber will already have access to.

Rubble pits

If your home was built before 1975, you might have a rubble pit or shallow trench filled with rocks through which the stormwater drains. Unless you carry out a reconfiguration of your land (subdivision, significant building or renovating), these pits are still considered a ‘lawful point of discharge’ if the ability to direct the stormwater straight to council stormwater drains was not available for the original build.

Common mistakes to avoid when planning Brisbane stormwater drainage

Unfortunately, stormwater drainage is not effectively regulated in Queensland. There are many cases of people taking the DIY route with catastrophic outcomes.

Ineffective roofwater drainage can be due to a number of factors. The most common issues we see include:

  • Undersized pipework
  • Running of discharge to undersized rubble pits
  • Lack of fall or backfall
  • Undersized in-ground stormwater sumps
  • Non-existent or poor waterproofing of retaining walls
  • Undersizing of spoon drains and grated drains
  • Lack of maintenance of stormwater systems

The consequences of inadequate stormwater drainage range from expensive to catastrophic so think twice about DIY! For ultimate peace of mind, call in the experts.

Fixing an existing stormwater drainage issue

At Salmon Plumbing, we use high-pressure drain cleaning equipment that can quickly and effectively clear stormwater systems and get them flowing to help prevent expensive flooding and damage to your property. While we are on site, we can look over your existing roofwater drainage plan and advise on how it can be improved.

If you need expert assistance with your stormwater drainage, Brisbane specialists Salmon Plumbing should be your first call. Get in touch today!