Pressure Sewer Systems

Pressure sewer systems are small on-property units that collect, grind and pump household sewage into a pressurised reticulation system in the street which then conveys the household sewage on to a treatment plant.

Pressure Sewer Unit

Pressure sewerage systems are not common across the city but generally in areas where a conventional gravity system is not a viable servicing option such as flat or rocky terrain.

The Pressure Sewer Unit (PSU) and all relating components are owned and maintained by Shoalhaven Water in their entirety. At no times are the PSU or other components to be adjusted, serviced or relocated by any persons other than Shoalhaven Water operations staff.

Pressure Sewer System Installation Guidelines

A development that is identified as requiring the installation of a low-pressure sewer unit (PSU) or any proposed work to an existing PSU must lodge an application with Shoalhaven Water prior to commencement of any works, this will include installation, modification or relocation of works.

Step One – Submit our online Pressure Sewer System Installation Request

Your online request will require you to upload a plan showing the location of the proposed pressure sewer unit including the alarm/control panel, pressure service lines, power supply, meter box and power lines from the meter box to the alarm panel and pressure sewer unit in relation to the Lot and proposed residence.

Requirements for the installation Site Location Plan include:

  • The pressure sewer unit must be located so that the residence and any other building can fully drain by gravity to the unit.
  • The pressure sewer unit must be located no closer than 5 metres to the residence. 
  • The pressure sewer unit and the alarm panel must not be more than 10 metres apart.
  • The pressure sewer unit must be in direct line of site from the alarm/control panel. No obstructions are permitted between the unit and the control panel.

Step Two – Payment Advice 

On receipt of your request, we will provide a payment advice which must be paid prior to any works commencing. Charges include the current market price of the required unit plus any additional costs for site works such as design, difficult terrain (ie rock conditions) or any additional work. 

Step Three - Installation of the Pressure Sewer System

The full installation of a pressure sewer unit will occur within approximately 8 weeks from the time an application is made. Planning by customers or developers well ahead is recommended. 

Once an installation is approved and payment received, Shoalhaven Water will install the pressure sewer unit in accordance with the Site Location Plan supplied. 

Electrical Installation Responsibility

Shoalhaven Water will install the control panel, connect the supply to the pumps and test electrical operation at completion of installation. It is the responsibility of the owner/builder to arrange for a qualified electrician to install a separate dedicated circuit (as specified below) from the electrical meter box to the location of the control panel. 
Once connected and operating, all power costs for the running of the pressure sewer unit are the responsibility of the property owner. 

Electrical Installation Requirements:

  • Single Pump Unit (Simplex) - supply to be 240 volt from a dedicated circuit using a 'D' curve 20A circuit breaker, conduit to control panel to be a minimum 25mm heavy-duty.
  • Dual Pump Unit (Duplex) - Supply to be 240 volt from a dedicated circuit using a 'D' curve 32A circuit breaker, conduit to control panel to be a minimum 50mm heavy-duty.
  • Control panel mounting location requirements:
  • Supply shall be taken to a point 150mm below the mounting location of the control panel and have at least 1 metre of cable left available for connection of panel.
  • The bottom of the panel must be 1200mm from ground level.
  • The panel must be mounted on wall, permanent structure or a minimum 200x100 galvanised post to a height of 1500mm above ground level.
  • Panel mounting location is to be no further than 10 metres from the tank.
  • Control panel must be accessible for maintenance and repair work to be undertaken by Shoalhaven Water. 


Using the Pressure Sewer System

There are a few things to know to ensure the system runs smoothly.

The system operates like a normal sewerage system taking waste liquids from your toilet, sink, shower, bath, dishwasher and washing machine and transferring it to the reticulation system or treatment plant. 

To avoid blockages and damage to the pressure sewer system, the following items should not be placed in the system:

PSS items to avoid


What to do if the alarm sounds

Firstly, turn off the sound of the alarm by pressing the mute button underneath the alarm panel. For a power outage the pressure sewer unit will automatically clear itself and the alarm will switch itself off within an hour. You will know if it has happened because the alarm light will go out. 

If the alarm light is still active after an hour, then call us. Do not attempt to repair the unit yourself. The system has a 24-hour emergency storage capacity so any repairs will be carried out within the 24-hour period. At this time, you should try to minimise the amount of wastewater going into the system. 


Maintaining the System

PSS warnings

Ensure access - We recommend you always maintain access to the pump unit and keep plant growth and other debris away from the unit. 

If you go on holidays, even if it is only for a few days, you will need to flush the system before you go away. This is to avoid the possibility of the system becoming smelly in your absence. You can flush the system by running water in the sink for about 10 minutes. 

Home modifications - Contact us if you are making modifications to your home which may affect the system, eg. if you are installing a spa or swimming pool or extending the house over of near the unit or discharge pipe.