Onsite Sewage Management

Some parts of Hornsby Shire do not have sewerage services and it is the responsibility of property owners to choose a method to treat wastewater.

Approval to install

Council approval is needed to install a new onsite sewage management system or upgrade your existing system.
Download an onsite sewage installation form

Approval to operate

All owners of sewage management systems must apply to council for an approval to operate, which helps Council monitor and manage the impact of pollution in local areas. The approval also ensures property owners are aware of their responsibility to operate and maintain their system.
Download an onsite sewage operation form

Common types of onsite sewage treatment

Septic tanks

Wastewater passes through a septic tank and is gravity-fed or pumped to sub-surface trenches.

Aerated wastewater treatment system

Wastewater is aerated and disinfected, then used to irrigate gardens and lawns.

Compost toilet

Solids are removed from the wastewater stream and transformed into compost by micro-organisms.


Wastewater passes through a septic tank into a holding well and is collected by a tanker on a regular basis.


Domestic wastewater from the hand basin, kitchen, bath, shower and laundry is recycled. Greywater can be used for irrigation, toilet flushing and washing machines. It cannot be used for drinking water, watering vegetables or topping up rainwater tanks or swimming pools.

Are you concerned about a neighbour's onsite sewage?

If you have concerns about the onsite sewage management on a nearby property you can ask Council to investigate. Click here to lodge a sewage investigation request

Further information

Phone Council's Environmental Compliance Team on (02) 9847 6829, email or visit