What it contains

Industry, businesses and local governments may need to discharge wastewater into the environment. If you need to do this, you may need to get permission from EPA Victoria. 

As part of that permission, you will need to do an environmental and human health risk assessment. The risk assessment processes can be complex. So, EPA has published Guidance for environmental and human health risk assessment of wastewater discharges to surface waters (publication 1287). It includes case studies and will help you assess risks if you are:

  • discharging wastewater from a point-source
  • discharging wastewater into surface waters. Examples of surface waters include streams, lakes and oceans.

Wastewater is treated waste that is mostly water. It often comes from industrial or business processes, or local government services. Examples of wastewater include:

  • water from sewage treatment plants
  • water containing any commercial, industrial or trade waste
  • cooling-water from power plants.

Wastewater can carry pollutants such as bacteria or chemicals. Pollutants in wastewater have the potential to harm human health and the environment.

Conducting a risk assessment is a useful way to identify potential harm. Once you know the risks, you can control or prevent harm from occurring.

There are three types of risk assessment that you can do. They each use different types of data:

  • Qualitative risk assessments use opinion to determine risk. Opinions may come from experts or stakeholders.
  • Quantitative risk assessments use data and maths to quantify risk.
  • Semi-quantitative risk assessments use a mixture of both.


The type of risk assessment you do will depend on the specific scenario of the wastewater discharge.

Risk assessments usually have three main phases:

  1. Problem formulation: what are the hazards and potential harms? What monitoring is needed?
  2. Risk analysis: what are the chances that harm will occur? And what would the consequences be for people and the environment?
  3. Risk characterisation: this final phase evaluates the risk analysis. This is useful for decision-making and risk management.


After you do your risk assessment, you may also need to write up how you will manage the risk.

You will need to submit your risk assessment and any risk management measures to EPA. EPA will use these to decide whether to grant you permission to discharge. And then, to check that you are maintaining compliance with your permission.

EPA publications are available to help you with your risk assessments and management:

Publication number
Water; Wastewater
Number of pages
Release date
16 May 2023
Document version

Reviewed 16 May 2023