Dewatering

About dewatering

Dewatering refers to removing groundwater to manage or complete construction or excavation activities. It is common in projects such as:

• mining
• construction of pipelines
• major road infrastructure
• large-scale excavation for residential and industrial development
• stormwater and sewerage treatment infrastructure maintenance.

Intercepting groundwater will generally require temporary or permanent dewatering – the removal of water from a location - to be carried out to complete or manage construction activities. Both temporary and permanent dewatering need licences and approvals.

The information on this page is an introduction to the requirements for groundwater dewatering, including links to information on how to apply for approval.

Dewatering regulation and management

Groundwater dewatering is regulated under the Water Management Act 2000 and managed by the department and WaterNSW.

The role of the department includes:

• issuing licences and approvals for:
  • government agencies – local, state, and Australian
  • water utilities, water supply authorities and licensed network operators under the Water Industry Competition Act 2006
  • mining activities
  • irrigation corporations
  • public schools and hospitals
  • Aboriginal communities and businesses
  • State significant development and infrastructure

The role of WaterNSW includes:

• issuing licences and approvals for all other people undertaking dewatering including most large-scale basement construction for high rise development. More information at: WaterNSW water supply works and water use approvals.

Find more information about what each agency does at: Water agencies

Exemptions

Dewatering activities do not need a licence or approval under the Water Management Act 2000 in these circumstances:

• Emergency works, taking of groundwater or overland flow water for the purpose of carrying out emergency works, noting:
  • the person claiming the exemption provides certain information to the Natural Resources Access Regulator before (or soon after) commencing relevant works and within 14 days
  • before undertaking any works review the detailed explanation of this exemption at: Emergency works exemptions

Find out if exemptions apply to your activity

If the temporary dewatering activities are not exempt, you need to apply for water supply work and/or water use approval and have a water access licence to account for the water extracted if the extraction is > 3 ML/year.

Types of dewatering activities

Dewatering activities requiring licencing and approvals

Dewatering activities that are not exempt need a water supply work and/or water use approval and a water access licence.

Information on how to apply for this licence and approval are available here:

• Water supply work and/or water use approval
• Zero share access licence (if required)
• Water access licence dealings

Dewatering as part of a State significant development and infrastructure projects

If dewatering is identified, and the impacts are assessed as a part of a state significant development or infrastructure (SSD/SSI) project a water supply work and/or use approval is not required.

However, a water access licence with sufficient entitlement to account for the water take is still required unless an exemption under the Water Management (General) Regulation 2018 applies. A common exemption relating to building dewatering is for the take less than 3ML/year.

Learn more about water requirements for state significant development and infrastructure at: Major projects

Related guides and resources

Use these resources to help with your application for a licence and/or approval for dewatering:

• Exemptions factsheet