CWMS - plumbing and maintenance


Septic systems

Septic systems treat and dispose of wastewater from toilets, bathrooms, laundries and kitchens. Simple care and maintenance of the septic system can prevent contamination to the environment and protect family health and safety.

A septic system is made up of various components including:

  • Septic tank
  • Internal drains
  • Tail pipe
  • CWMS main and connection point. 

Septic tanks

A septic tank is an underground watertight tank made from either concrete or plastic. Septic tanks are usually located within the boundary of a property.

Wastewater from toilets, laundry, bathrooms and kitchen is gravity fed into the septic tank for treatment, where the liquid and solid portions of the waste are separated.

The solids settle to the bottom of the tank where naturally occurring bacteria convert the material into sludge, while the liquid effluent passes out of the septic tank, through the system’s outlet drain and into Council’s Community Wastewater Management System (CWMS).

Access hatch

Septic tanks require a hatch to provide access for cleaning - pumping out.

A licensed contractor must complete the pump out, and if the property is connected to Council’s CWMS, this will be organised by Council and done every four years. Council’s contractors are licensed by the EPA to remove, transport and dispose of the waste.

In general, if your septic tank is working well, you should not need to open your septic tank. If you are required to open the access hatch, take care as wastewater can produce harmful gases.

It is a requirement that all new septic tanks have their access hatch raised to ground level. This must not be covered by anything that cannot be quickly and easily removed.

Older septic tanks may not have their access hatch at ground level. For ease of access, it is recommended that home owners engage a contractor to raise the access hatch(PDF, 418KB) 

Inspection point

The inspection points (IPs), located on the inlet and outlet drain of a septic tank, enable access to the sanitary drain to clear any potential blockages.

A licensed plumber can assist in clearing these blockages if they occur.

If you do not have visible IPs at these points, consider speaking to a licensed plumber about raising them to ground level. You will need additional Council development approval to complete CWMS development work.

Connection point

The connection point is where wastewater enters Council’s CWMS. The connection point must not be covered as Council may need to access it from time to time.

Any maintenance of the CWMS drain, from the connection point is Council’s responsibility, whereas any maintenance from the connection point up to and including the household drains is the responsibility of the property owner - see figure 1 below.

Figure 1: Diagram illustrating what is Council’s responsibility and what is the property owner’s responsibility.

 cwms - figure


Please note, if you wish to raise the ground level of your property -eg when building a retaining wall or building a garden bed, you will need to gain separate Council approval for CWMS works.

If approved, you will be required to pay for the connection point to be correctly positioned at the new ground level.

The photos below are examples of what a connection point may look like when it is raised to ground level.

cwms figure 2 flow

Maintaining a septic tank and its associated drains is important because it will save time and money and help protect the health of your family.
Damaged drains should be repaired quickly to help prevent reoccurring blockages. SA Health’s fact sheet has some valuable information regarding maintenance of your system. 

Septic tank pumps

Whenever possible, a septic tank system should be designed with sufficient grade on the drains so that wastewater can flow to the CWMS by gravity.

A pump system may need to be installed when there is insufficient fall for the wastewater to flow from the septic tank to the connection point. Please note, approval is required to pump wastewater into Council’s CWMS network.

Replacing a septic tank

As the tank ages it may need to be replaced. Replacement of a septic tank requires requires approval from Council 
The septic tank must be on SA Health's list of approved products. The septic tank and all other plumbing must be installed by a licensed plumber.

Stormwater into CWMS

Residents must not allow any rainwater, stormwater or surface water to enter the CWMS.

If stormwater enters the CWMS, the network can become seriously overloaded during and after rain events. 

When the CWMS is overloaded, septic tanks cannot efficiently drain into the network and this appears as though the drain is blocked. In extreme cases, the CWMS may overflow creating an environmental hazard.