Building in a non-sewered area

Homes with on-site sewerage come with obligations for the owner or tenant to ensure environmental compliance and neighbourhood harmony.

As a homeowner or tenant it’s important that youare aware of your requirements for maintaining these systems.

What is an on-site sewerage facility?

Homes not connected to Council’s sewer network require an on-site sewerage facility, which are wastewater treatment systems for domestic sewage. The facilities treat and dispose of wastewater from the laundry, kitchen and bathrooms including sinks, showers, baths and toilets. These facilities usually comprise of at least one in-ground tank and a disposal area within the property.


To ensure the on-site sewerage facility operates as designed and to protect public health, it must continue to comply with the Queensland Plumbing and Wastewater code and its referenced Australian Standards, the manufacturer’s specifications and, where applicable, the Local Government approval conditions after it is installed.

Servicing (maintenance)

It is the property owner’s responsibility as stipulated in the Plumbing and Drainage Act 2018 to maintain an on-site sewerage facility. It is essential that the facility is regularly maintained in accordance with the manufacturer’s specifications and approval conditions.

Maintenance requirements differ depending on the type of on-site sewerage facility you have. State legislation requires that the system be serviced as recommended by the manufacturer’s specification.

A licensed service agent must be engaged to carry out the maintenance and, depending on the system, to provide Council with a report of the performance of the system.

The servicing agent who maintains the treatment plant must hold a current license in one of the three following categories, issued under the Plumbing and Drainage Act 2018:

  • Plumber and drainer’s license with an on-site sewerage facility endorsement;
  • Drainers licence only with an on-site sewerage facility endorsements; or
  • Restricted drainer’s licence for on-site sewerage facility (with ‘maintain’ condition stated on the licence)

Caring for your system

Make sure the household products you use do not impair the performance of your on-site sewerage system. Ask your service agent if you are unsure, or refer to the owner's manual or our do and do not fact sheet for general advice.

Many older properties have an existing on-site sewerage facility called a septic tank with a greywater holding tank, also known as a sullage system, that requires pumping out.

Septic Tank

A septic tank (or black water) is a system that uses useful bacterial to break down and process the bio products of human waste into a stabilised liquid (known as effluent). The effluent is discharged from the tank into evaporation, a transpiration and or absorbtion trench system.

An absorbtion trench lets the effluent absorb into the soil. The grass and plants use the moisture and nutrients, and the wind and sun assist with evaporation.

Septic tanks need to be checked annually. How often they need to be cleaned depends on the tank’s capacity, the flow of wastewater and the volume of solids in the wastewater.

Some systems may need the solids (sludge) to be removed. This process is recommended every three to five years.

Sullage system

A sullage system (or greywater) disposes of the domestic waste from kitchens (via a grease trap), baths, showers, basins and laundries.

A grease trap is a small tank, usually installed close to the kitchen, to take greywater from the kitchen sink and prevent grease entering the trenches.

You should clean the traps every three to six months and call the plumber if the trap is blocked.

Neighbourhood harmony

Effluent must be disposed of within the boundaries of the property from which it was generated. It is an offence to dispose of effluent onto neighbouring properties, gutters or into waterways, or where it could run off into waterways.

Council is available to provide advice on any on-site sewerage facility and how it should be maintained. For further information please contact Council’s Water Services team on 1300 883 699.

On-site sewerage facility - do's and don'ts

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