Our flood maps can tell you:
- if a property has a chance of flooding
- where on a property flooding might happen
- how high the water could rise
- recommended finished floor levels for building or renovation projects.
View flood maps
If you're planning to build or renovate in a flood-prone area, it's important to do more research. Make sure your plans meet the requirements in the Toowoomba Regional Planning Scheme to keep your property safe and compliant.
How different types of flooding may affect a property
Flood studies show that flooding in the region is complex and can change a lot from place to place, depending on the land, buildings and rainfall patterns. Past floods happened because of heavy local rain causing water to run through yards and streets and from creeks and the Condamine River overflowing. These types of flooding can happen on their own or together, which means the impact on properties can vary. Your property might experience one type of flooding or a mix of both.
Properties identified for flooding without prior flood events
Properties that haven't experience flooding, may flood in the future. Flood studies show different scenarios to estimate which areas might be affected during various types of floods. Over the years, we have carried out studies to better understand rainfall patterns and the shape of the land so we can predict where water is likely to flow.
Properties on hills
Heavy rain at the top of a hill will flow downhill and collect in low areas like gullies, channels, roads, and dips in the ground. The water can still be deep and fast enough to cause damage. Your home might also become cut off if roads flood, making it hard to leave. Your safety is the most important thing, especially if you could be isolated for a long time.
Risk for properties without flood indicators on mapping
Flood maps and models show where flooding from rivers, creeks, or stormwater might happen during different rainfall events, and some studies use real historic floods. There are also areas between towns with creeks or flow paths that haven’t been studied in detail but can still flood. It’s always possible that flooding could happen in places not shown on the current maps, though the risk there is much lower.
Even if your property doesn’t flood, you might face problems like road closures or isolation. Knowing these risks helps you plan ahead and stay safe, for example by making sure you can evacuate if your property becomes cut off.
Flood risk means how likely flooding is and how much damage it could cause to people, homes, and infrastructure. Risk is usually higher in built-up areas. Managing flood risk involves things like:
- controlling floodwaters (e.g., levees)
- making properties safer (e.g., raising floor levels)
- improving emergency plans.
Flood hazard is about how dangerous the floodwaters are. It depends on things like:
- water depth and speed
- how quickly water rises
- the shape of the land.
Hazard levels are usually rated as low, significant, high, or extreme.
Key difference between flood risk and flood hazard:
- Hazard exists no matter what - even in undeveloped land.
- Risk depends on what’s exposed - two places with the same hazard can have different risks if one has homes and the other doesn’t.
If a property is marked 'at risk', it means flood models show water could cover part of the land. Whether water gets inside a building depends on things like slope, drainage, and floor height.
Understanding flood risk ratings
If you have plans to build or renovate in a Flood Risk Area, we recommend further investigation be undertaken to ensure the requirements outlined in the Toowoomba Regional Planning Scheme are met.
A summary of the planning and development requirements for each risk rating is provided below.
Low flood risk (FR1)
Low flood risk occurs mainly on higher land that is only flooded in very large, unlikely floods, with water that is slow and shallow to moderately fast and deep.
Planning and development requirements
- When constructing a new building or extending an existing building:
- the finished floor level should be at least 300mm above the level of the defined flood event
- residential buildings are not slab on ground
- associated earthworks don’t worsen flood risk on adjacent properties
- compliance with the relevant building assessment provisions is required.
- When filling land, no more than 50 cubic metres of material is added.
- When subdividing land, new lots should have a finished ground level above the identified flood level.
- Locate/design essential infrastructure so it is not impacted by flooding.
Medium flood risk (FR2)
A location has a medium flood risk if it may be affected by both moderate floods that happen more often and very large floods that are rare.
For the likely flood events, the hazards tend to be low, however as the floods become less likely, the hazards increase in their impact on life and property.
Planning and development requirements
- When constructing a new building or extending an existing building:
- the finished floor level should be at least 500mm above the level of the defined flood event
- residential buildings are not slab on ground
- associated earthworks don’t worsen flood risk on adjacent properties
- compliance with the relevant building assessment provisions is required.
- When filling land, no more than 50 cubic metres of material is added.
- When subdividing land, new lots should have a finished ground level above the identified flood level.
- When land in greenfield areas is subdivided, parts of the land subject to this flood risk is protected from future development.
- Locate/design essential infrastructure so they are not impacted by flooding.
High flood risk (FR3)
A location has a high flood risk if it is affected by significant hazards in moderate floods and high hazards in larger, less common floods.
Planning and development requirements
- No new urban activities occur within this area.
- No new buildings are constructed in this area.
- No filling of land occurs in this area except where a floodplain management plan shows that it is acceptable.
- When subdividing land, new lots should have a finished ground level above the identified flood level.
- When land in greenfield areas is subdivided, parts of the land subject to this flood risk is protected from future development.
- No essential infrastructure is located in this area.
Extreme flood risk (FR4)
A location is considered to have extreme flood risk if it is affected by high to extreme hazards in moderate floods, or extreme hazards in large floods.
Extreme flood risks at a location are defined for the high-to-extreme hazard areas of the moderate floods and the extreme hazard areas of large floods.
Planning and development requirements
- No new urban activities occur within this area.
- No new buildings are constructed in this area.
- No filling of land occurs in this area except where a floodplain management plan shows that it is acceptable.
- When subdividing land, new lots should have a finished ground level above the identified flood level.
- When subdividing land in greenfield areas, the land subject to this flood risk is protected from future development.
- No essential infrastructure is located in this area.
Balanced (mixed)
This applies to mainly rural land that may be affected by a flood with a one in a 100 chance where flooding is known to occur, but detailed risk mapping has not been done.
Planning and development requirements
- All development is encouraged to occur on that part of the land which does not have a designated flood risk.
- Where development is proposed within that part of the land which has a designated flood risk, a site-based assessment must be undertaken to show that what is proposed is appropriate given the level of flood risk.
Overland flow (low)
This applies to locations where the depth of overland flow is shallow, between 70mm and 300mm, but the speed of the water can be from slow to moderately fast.
Planning and development requirements
- When constructing a new building or extending an existing building:
- the finished floor level should be at least 600mm above the natural ground level
- associated earthworks must not worsen the flood risk on adjacent properties.
- When filling land, no more than 50 cubic metres of material is added.
- Vulnerable uses are avoided e.g. childcare centres, aged care facilities. Learn more about the vulnerable use definition(DOCX, 214KB).
- Locate / design essential infrastructure so they are not impacted by flooding.
Overland flow (high)
This rating applies to locations where the overland flow can be fast flowing or deep (greater than 300mm) or a combination of both.
Planning and development requirements
- When constructing a new building or extending an existing building:
- the finished floor level should be at least 300mm above the level of the overland flow event
- associated earthworks must not worsen the flood risk on adjacent properties.
- No filling of land occurs in this area.
- When subdividing land, new lots should have a finished ground level above the identified flood level.
- When subdividing land in greenfield areas, the land subject to this flood risk is protected from future development.
- Vulnerable uses are avoided e.g. childcare centres, aged home facilities. Learn more about the vulnerable use definition(DOCX, 214KB).
- No essential infrastructure is located in this area.
Vulnerable use restriction area
This rating applies to all land affected by flooding, including land that is only flooded during an extremely rare, worst‑case flood event (probable maximum flood), but excludes land that is only subject to overland flow (low).
It is used to prevent land uses that are especially vulnerable to flooding from being located in flood‑risk areas. This includes uses such as childcare centres, aged care facilities, hospitals and schools. Learn more about the vulnerable use definition(DOCX, 214KB).
Planning and development requirements
- Vulnerable uses are avoided.
Flood island
Flood island refers to land that is not flooded by water but becomes cut off during a flood.
Planning and development requirements
- Vulnerable uses are avoided.
We are committed to the goal of a 'Safer, Stronger, More Resilient Region' by continuing to improve flood management and community awareness of flood risk. This means building a region that is financially, socially and environmentally sustainable.
We released flood studies for 35 locations across the region for community feedback in February 2015. These flood studies were undertaken by specialist engineers and incorporate the latest data, modelling techniques and the community input assisted in their finalisation.
A flood study looks at how floods behave in a certain area, like a river or creek. It helps us understand how deep, how far, and how fast the water can go. This information is used for planning buildings, land use, safety, and emergency response to keep people and property safe. Flood studies create maps that show where water will spread, how deep it will be, how fast it moves, and how dangerous it is. These maps make it easier to see what flooding might look like and how it could affect your property.
View all flood study reports.
Identification of flood study areas and study types
Specialist engineers were hired to figure out what we needed to do to meet legal requirements and these reports are available to the public. The engineers investigated flood history, the type of flooding (such as overland flow, creek, or river), existing data from flood gauges, population size, the catchment layout and whether accurate Light Detection and Ranging (LiDAR) survey data was available.
Based on this, they decided what kind of study was needed, such as an overland flow path study, a 2D flood study or a historical study. In some places, like Millmerran, more than one type of study was done.
Historic flood studies
Historic flood studies use local knowledge, old records and stream flow data to understand how a past flood happened, including its depth and danger. These studies often use a hydraulic model to recreate a specific flood event in a catchment using the best data available, like surveyed flood levels and community information. The results are then compared to different simulated flood scenarios to work out how likely that historic event was - whether it was a smaller, more common flood or a bigger, rare one.
2D flood study
Two-dimensional (2D) flood studies are detailed and give the most reliable results. They use special modelling tools to study how water moves and include a full analysis of the data. These studies show important information like how much water flows, its depth, speed, and danger levels under current conditions. They also look at different types of rainfall events, from small, frequent storms to big, rare ones.
Requesting updates to flood study data
If reliable evidence is provided that would improve a study, we will review it. If the community thinks other areas need more detailed investigation, we will look into doing more studies.
Toowoomba Region flooding history
In December 2010 and January 2011, parts of the Toowoomba Region experienced severe flooding that caused loss of life and major property damage. In response, Council started a large program to improve flood management, update development rules for flood-prone areas, and raise community awareness. This program included flood studies for 34 urban areas and the Condamine River catchment, leading to changes in the Toowoomba Regional Planning Scheme through Amendment No.17.
Since 2015, Council has worked with property owners, communities, and other stakeholders to collect flood information and validate studies. Several rounds of community consultation were held between 2015 and 2019, involving thousands of people through meetings, open house events, and online feedback. This input helped update flood studies and shape planning rules to better manage development in flood-risk areas. Council considered submissions and made changes to the planning scheme based on community concerns.
The updated planning scheme now includes a Flood Hazard Overlay, which identifies flood-risk areas and sets standards for new development to protect people and property. The amendment was adopted on 21 July 2020 and came into effect on 21 August 2020. These changes aim to reduce flood impacts and improve future planning across the region.
1 in 100 year flood
There’s no such thing as a 'one in a 100 year flood', even though people often use that term. Every flood is different, and we can’t predict exactly when the next one will happen. What we can do is estimate the chance of a flood of a certain size happening in a specific area in a year. The correct term for this is Annual Exceedance Probability (AEP). For example, what people call a one-in-100-year flood actually means there is a 1% chance of a flood that size or bigger happening in any given year.
Average Exceedance Probability (AEP) explains the chance of a flood of a certain size (or bigger) happening in any year, shown as a percentage. For example, the Bureau of Meteorology says that every year there is a 1% chance, a one in 100 chance, that a flood of that size or larger could occur one or more times.
The chances of different sized floods happening over time can be worked out with maths. For example, if you live in a place with a 1% chance of flooding each year and stay there for 70 years, there’s about a 50% chance you’ll experience at least one flood. But flooding doesn’t just affect homes, it can block roads, stop food from reaching markets, and impact tourism. With more than 100 rivers and creeks in Queensland, when flooding happens, many people are likely to be affected either directly or indirectly.
Speed of floods
There are different types of floods. Flash floods happen when very heavy rain falls suddenly, causing water to rise quickly, like what happened in January 2011. In bigger catchments, rain can build up over hours or days, and the runoff can flood large areas for a long time. In our region, rising water in river basins often cuts off towns like Cecil Plains, Quinalow, Maclagan, Clifton, and Jondaryan. These slower floods give more time for warnings and preparation. Sometimes, a flash flood upstream can turn into a larger river flood as it joins other water and spreads downstream. Many places in our region can experience both flash floods and river or creek flooding.
Climate change
Some flood studies include climate change impacts, like heavier rainfall, in their scenarios. We understand that the climate is changing, so it’s good engineering practice to check how future conditions could affect creek and river flooding.