School operations

Wastewater Treatment Systems

Including septic tanks and treatment systems for wastewater

Risks and hazards


To ensure their systems are managed safely, schools need to be aware of the risks associated with their installed on-site wastewater management systems (OWMS).

A poorly installed or maintained OWMS system can be a risk to human health and the environment. This is especially true of older systems. The risks can include:

  • adverse impact on human health
  • polluted drinking water
  • land and waterway contamination
  • offensive smells.

Preventative measures such as routine maintenance can reduce the risks and hazards associated with an OWMS. These measures are outlined below.

Wastewater overflow risks and hazards

Contact with wastewater can occur when effluent or untreated wastewater overflows or is improperly discharged, resulting in seepage onto the property. The common cause of on-site wastewater overflows is the failure, or inadequate maintenance and servicing of the OWMS.

Wastewater contains dissolved and suspended biological matter that can contain many microorganisms that may be harmful to humans, animals, and the environment. These microorganisms can include viruses, bacteria, protozoa, fungus, and parasitic organisms.

Contact with wastewater or its products can expose people to harmful microorganisms that can cause illnesses such as:

  • gastroenteritis (diarrhoea or vomiting)
  • giardiasis and cryptosporidiosis (severe stomach cramps, diarrhoea, or vomiting)
  • viral infections such as hepatitis (liver infections)
  • infections of the skin or eyes.

Risk warning signs

Schools must monitor their systems for potential failures, especially in older systems. Some early warning signs of a potential failure including:

  • foul smells coming from or near the system
  • slow running toilets or drains
  • full or blocked grease trap
  • wastewater runoff from the disposal area
  • wastewater pooling on the disposal field's surface.

Schools must take steps to address any issues as soon as possible.

Refer to the emergency management chapter and defects chapter for further information on managing system failures.

Minimising risks associated with on-site wastewater management systems

Schools must take practical and preventative measures to minimise the risks posed by OWMS such as:

  • ensuring system can be accessed easily
  • when signs of system failure are identified, use a Victorian Building Authority (VBA) registered plumber to assess whether a system needs cleaning and unblocking – refer to the section on risk warning signs above
  • desludging the system every 3 years or once deemed required following inspection by a VBA registered plumber or equivalent (how often depends on the level of system use)
  • taking all reasonable steps to ensure the system is maintained properly and keeping all system maintenance records
  • having an Environment Protection Authority (EPA) accredited waste management consigner install an alarm and flow meter to warn of breakdowns to critical operating components such as pumps
  • arranging the maintenance of the disinfection chamber (if any) – this chamber uses chlorine to disinfect the treated water, and chlorine tablets must be fitted to the dispenser in the right way
  • for disinfection chambers fitted with UV disinfection, UV light tubes must be cleaned quarterly by a VBA registered plumber or equivalent
  • not driving vehicles over any part of the system
  • not allowing stormwater to discharge into the on-site system or over the disposal/drain field
  • not obstructing or covering the tank or drain field
  • not placing non-biodegradable items or rubbish into the system – bacteria and other organisms are unable to break down these items or rubbish
  • ensuring that Local Government Authority or EPA maintenance requirements are followed as per the issued permits and licences.
Includes information on risks and hazards associated with installed on-site wastewater management systems

Reviewed 09 January 2023

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