Every day, 1.87 million Melburnians flush or drain 2.4 billion litres of wastewater that goes to our water recycling plants for treatment.

What is a pressure sewer system? 

A pressure sewer system uses an underground pump and tank to collect wastewater from your property. This includes everything from toilets, sinks, showers, dishwashers and washing machines. The system then moves the wastewater through sealed pipes to the main sewer or treatment plant.

Pressure sewer systems are commonly used in areas where traditional sewers aren’t suitable — like flat ground, rocky terrain, steep slopes, wet conditions or environmentally sensitive areas.

A typical pressure sewer system includes:

1. OneBox® control unit (or similar control box) – a small telecomms box wall mounted and contains controls and alarms for the pressure sewer unit.

2. Pressure sewer unit – underground tank with electric pump and level monitors - only the lid is visible for servicing.

3. Property discharge line – connects the pump and tank to the sewer main.

4. Boundary kit – contains a non-return valve to prevent sewage back-flow and allows isolation during maintenance.

Benefits of a pressure sewer system

Pressure sewer systems are modern, reliable, and designed to solve problems that traditional sewer systems can’t.

Here’s why they’re a smart choice:

  • Great for areas where gravity sewers don’t work (flat, hilly, rocky or wet ground) 
  • Less digging and disruption during installation — minimal impact to gardens, landscaping and driveways 
  • Quiet operation — you’ll barely notice it’s running 
  • Smart tech alerts us to issues automatically 
  • Low maintenance once installed 
  • Fully sealed system helps protect local waterways and the environment

Who looks after the pressure sewer system? 

South East Water is responsible for:

  • Covering the cost to build and maintain the pressure sewer network
  • Installing and maintaining the pump unit, boundary kit, discharge line and control panel 
  • Providing a connection point to the main sewer in the street 

Important: All parts of the pressure sewer system belong to South East Water and are looked after by our trained team. Please don’t try to move, adjust, or fix anything yourself — only our authorised staff should do any work on the system.

The property owner is responsible for: 

  • Supplying power to the system 
  • Maintaining the household plumbing up to the sewer tank
  • Keeping the area around the system clear and easy to access 
  • Complying to relevant build over guidelines

Renting?

Chat to your property manager or rental provider about any work or repairs needed.

Using your pressure sewer system

What can I put in my sink and toilet?

Putting the wrong things down sinks, drains or toilets can block your system and cause expensive repairs.

Never put these into your system:

  • Fats, oils, or grease 
  • Wipes – baby, hand, cleaning, or toilet 
  • Glass, metal, plastic 
  • Nappies, sanitary items 
  • Seafood shells, kitty litter, rocks 
  • Clothing, socks, rags 
  • Paints or chemicals – except normal household use such as dishwashing powder, detergents, and hair dyes 
  • Petrol, diesel, or flammable liquids 

If your system fails because of these, you may need to cover the repair costs.

Blockages and faults: What to look out for?

We remotely monitor about 95% of our pressure sewer network to catch issues early.

Sometimes, you might notice a problem before we do — this can happen if there’s a communication issue or a fault with the monitoring equipment.

Keep an eye out for these common signs that your system might not be working properly:

  • Toilets not flushing as they should 
  • Sinks or baths draining slowly 
  • Sewage leaking near the tank or around your property 
  • An alarm sounding from the control panel

Had a power outage?

Some of these issues may appear temporarily after a power cut. Wait 2-4 hours to see if the problem resolves before reporting a fault

What to do if the blockage is in my home

It’s your responsibility to unblock it. If you’re the owner, you’ll need to contact a licensed plumber to fix the blockage. If you’re a renter, contact your rental provider or agent as soon as you can.

Problem still not solved?

If you're still experiencing problems with your pressure sewer, reach out to our support team.

Contact us

Need a printable summary? 

Download the Pressure Sewer Fact Sheet — a simple guide for owners, tenants, plumbers and contractors.

FAQs

Please report it as soon as possible by calling our Faults and Emergencies line on 13 28 12. 

You are as the property owner. The system must have its own dedicated power supply that stays connected at all times. You’re also responsible for any electricity charges related to the system. 

The tank can hold around 900 litres – roughly 24 hours of normal use. You can still use your toilet and shower. Try to avoid using appliances like washing machines and dishwashers if you have backup power.

Most units are about 1.2 metres wide and 1.45 metres deep and can store between 900 and 1,100 litres. They’re installed underground – you’ll only see the lid.

The pump makes very little noise and can usually only be heard when standing nearby. 

Usually around 15 to 20 minutes, depending on your water use.

No. Pools can’t be connected without prior approval due to the high volume of water.

Unapproved changes or damage may result in repair costs to you. 

Only South East Water authorised staff can access or work on pressure sewer assets. Homeowners are responsible for all plumbing upstream of the pressure sewer tank. An inspection shaft (IS) should be located at this point for inspection purposes.

If there’s a fault, please report it to South East Water.

No – only South East Water can work on or alter the system. Any building or landscaping near pressure sewer parts must comply with our Build Over Guidelines.

For advice on alterations or building over the system, call 1800 720 613 or email pressuresewerconnections@sew.com.au. 

You’re responsible for protecting all sewer assets – both above and below ground. Damaging assets can be dangerous, costly, and harmful to the environment, and you may be held liable. Refer to our Build Over Guidelines early in your planning.

If the system needs to be moved, modified or decommissioned during your works, get in touch with us by calling 1800 720 613 or email pressuresewerconnections@sew.com.au. 

Yes – we need 24/7 access to maintain the system. In some cases, we’ll also need to access your switchboard to isolate power. Most visits occur during daylight hours, but in rare cases we may attend after-hours to prevent overflows. The tank is designed to hold 24 hours of flow.

If a fault is found, whether by us or reported by you, we’ll arrange for a crew to inspect and fix the issue. 

You’ll receive an SMS and email from us before anyone visits your property.

Please let us know immediately if there are any access issues and secure your pets to help keep our crew safe. 

You can ask to see their South East Water photo ID. You can also confirm their job number or check using your address by contacting us directly.

Not connected to the pressure sewer network yet?

Find out how to join and start enjoying the benefits.
Visit our connections page on the South East Water website to learn more and get started.

Get started

Related information

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