Groundwater Housing Risk





[Overview] This dataset supports the Housing Approvals Reform Action Plan in meeting housing targets across the Greater Metropolitan Region. Building projects having groundwater interaction are subject to the NSW Aquifer Interference Policy assessment and environmental protection requirements. All of the groundwater-related factors that must be considered as part of planning for a building development are used as input layers—acid sulphate soils risk, contaminated sites risk, groundwater works risk, water features risk, groundwater dependent ecosystems risk and groundwater systems risk—and an overall risk dataset has been created from them. The accompanying Groundwater Housing Risk dataset method report provides a detailed explanation of the context of the overall risk layer and the analysis of the subordinate input layers.
[Currency] The Groundwater Housing Risk dataset is limited to the Greater Metropolitan Region water sharing plan area and is a static representation of the risk as at the time the analysis was completed (September 2025). The dataset is made available as a snapshot to assist building project assessment. Users of the dataset should not rely on the information remaining current for any substantial length of time and additional checks on the accuracy of the information should be carried out.
[Possible refinements] It is possible that the dataset will be expanded to other areas of the state at a future point in time. It is also possible that regular updates to the dataset will be automated at a future point in time to replace the static solution.
[Layer hierarchy] The Overall Risk layer shows all of the risk elements applying to a project location and is the priority layer for user assessments. Selecting a location in the Overall Risk layer opens a pop-up window that shows a list of all of the risk settings for the overall risk and the subordinate input layers in that location. For user assessments, the subordinate input layers do not routinely need to be displayed in the mapping, as the Overall Risk layer captures all of the information. However, they are available when individual visualisations of input layer risks are needed for specific reasons but should only be turned on one at a time to ensure the correct data is viewed.
[Colour themes] To avoid misinterpretation, the input layer risk settings have been given different colour themes to those of the Overall Risk layer and all have a degree of transparency. Users should be aware that, depending on the base map used during searches the colours may be affected and the risk settings should always be confirmed from the Overall Risk layer selection window. To counter this, the Overall Risk layer and the subordinate input layers should always be viewed individually as this will reduce the occurrence of colour changes in a visualisation.
[Visible scale range] All of the layers are available to view at a localised scale only for the purpose of assessing risk around a property. The visible scale range adopted for this purpose is 1:1,000 to 1:10,000. The layers are not available to be viewed over a larger area as the visualisation is affected by colour masking and does not retain any meaning at more zoomed out scales.
Description of Field headings/Attributes
[Groundwater Works Risk] The risk category (Medium or High) applied to buffer areas around groundwater works (water bores) that have been identified as having a current approval status at the time of layer development (September 2025). Areas outside of the mapped Medium-risk (250 m to 500 m) or High-risk (0 to 250 m) buffers are assumed to be Low-risk. Note that this is a static input layer and users should confirm the currency of the information in relation to their project for themselves.
[Contaminated Sites Risk] The risk category (Medium or High) applied to buffer areas around contaminated sites listed at the time of layer development (September 2025). Areas outside of the mapped Medium-risk (250 m to 500 m) or High-risk (0 to 250 m) buffers are assumed to be Low-risk. Note that this is a static input layer and users should confirm the currency of the information in relation to their project for themselves.
[Water Features Risk] The risk category (Medium or High) applied to buffer areas around surface water features (rivers, water bodies and the coastline). Areas outside of the mapped Medium-risk (250 m to 500 m) or High-risk (0 to 250 m) buffers are assumed to be Low-risk.
[Acid Sulphates Soils Risk] The risk category (Medium or High) applied to Acid Sulphate Soils probability areas. Areas outside of the mapped Medium-risk (low probability or other mapped extents) or High-risk (high probability mapped extents) buffers are assumed to be Low-risk. Low probability and other mapped areas are adopted as Medium-risk because the potential for localised acid sulphate soil deposits remains present in these areas and their occurrence can only be resolved with targeted investigations.
[Groundwater Systems Risk] The risk category (High) applied to groundwater systems (geological formations or mapped groundwater sources comprising unconsolidated sediments such as coastal sands and alluvium). No Medium-risk category is assigned alongside the boundaries of groundwater sources or geological formations because there is a step change and not a gradual change between the different hydrogeological settings either side of the boundary. Areas outside of the mapped High-risk areas are assumed to be Low-risk.
[Groundwater Dependent Ecosystems Risk] The risk category (Medium or High) applied to buffer areas around Groundwater Dependent Ecosystems (springs, vegetation and wetlands). Areas outside of the mapped Medium-risk (250 m to 500 m) or High-risk (0 to 250 m) buffers are assumed to be Low-risk.
[Overall Risk] An overall risk category (Low, Medium or High) for the Groundwater housing risk dataset based on the input variables (Groundwater Works Risk, Contaminated Sites Risk, Water Features Risk, Acid Sulphate Soils Risk, Groundwater Systems Risk and Groundwater Dependent Ecosystems Risk). Where input datasets overlapped, the highest risk category was applied as the overall risk setting.
[Water Sharing Plan] The Water Sharing Plan boundary that defines the study area used for the analysis, in this case the area of application of the Water Sharing Plan for the Greater Metropolitan Region Groundwater Sources 2023.

Tags: Building Development, DCCEEW - Water, DCCEEW - Water Science, Groundwater, Housing Risk, Risk Assessment
Organization: Spatial Services (DCS)