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Wastewater System / CWMS FAQs

The older areas of Mount Barker and townships such as Macclesfield, Echunga and Nairne are serviced by a Community Wastewater Management System (CWMS).

Council's CWMS is a wastewater drainage system. The CWMS takes liquid wastewater (effluent) from properties that have a septic tank system to SA Water sewer mains or an approved treatment facility.

Households on CWMS will have a septic tank which will require routine cleaning once every five years. Council manages this process to ensure the minimum cleaning requirements are adhered to.

If your property is connected to Council’s wastewater system and you are planning to develop i.e. sub-divide; build; alter an existing dwelling; install and/or alter a spa or swimming pool etc. you may require an approval from Council that is separate to a Development Application Approval. These activities and the relevant approvals are detailed in the table below:

Wastewater Operations
Environmental Health
Connection to wastewater system (includes new connections, drain extensions and modifications)x 
Trade waste approvals or changes in trade waste agreements x
Installation of a new trade waste system x
Building a new house x
Installation of a new septic tank x
Additions to an existing building that include plumbing works x
Installation or modification of a swimming pool 
Installation or modification of a spa x
Draining a swimming pool or spa x
Installation of a pumped septic system x


Subdividing properties connected to Council's wastewater system

As a part of the land division process, a Wastewater System Permit Application will need to be submitted for the installation of a new connection point into the system.

Costs associated with the alteration and/or new wastewater system connection are to be paid by the land owner prior to final clearance of the land division. Technical requirements for new connections can be found in the document below or you can contact Damian Lethbridge (Wastewater Infrastructure Officer) on 08 8391 7200.

CWMS Technical Requirements

Swimming pools and spas

If your property is connected to Council’s wastewater system and you intend to install a swimming pool or spa, a Wastewater Works Alteration/Addition Application will likely be required. For further information, please contact an Environmental Health Officer on 08 8391 7200.

Note, unauthorised discharges into the Council’s wastewater system is an offense under the South Australian Public Health (Wastewater) Regulations 2013.

If there is a blockage on your property, call a licenced plumber. It is important for plumbing work to be undertaken by a licensed plumber as this may have implications with your insurance or any warranties you may have.

Note that most of the newly developed areas have no septic tanks onsite and are directly connected to Council's sewerage pipe network. If you are on a CWMS scheme, inform the plumber that you have a septic system connected to the CWMS.

A septic system treats and disposes of wastewater from toilets, bathrooms, laundries and kitchens. Simple care and maintenance of your septic system can prevent contamination to the environment and protect the health and safety of your family.

A septic system is made up of various components including:

  • Septic tank
  • Internal drains
  • Tail pipe
  • Wastewater system main and connection point

Septic tanks have been used in un-sewered areas for many years as the first stage of treating domestic wastewater.

A septic tank is an underground watertight tank made from either concrete or plastic. Your septic tank should be located within the boundary of your property.

Wastewater from your 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 your system’s outlet drain and into Council’s Community Wastewater Management System (CWMS).

Your septic tank is required to have a hatch to provide access for cleaning (pumping out). A licensed contractor must complete the pump out, and if you are connected to Council’s CWMS, this will be organised by Council and done every five 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 (lid).

The inspection points (IP), located on the inlet and outlet drain of the 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 your licensed plumber about raising them to ground level.

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

Any maintenance of the wastewater system 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.)

Wastewater System Responsibilities

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

Please note, if you wish to raise the ground level of your property (e.g. when building a retaining wall or building a garden bed), you will need to contact Council for approval, and 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 your connection point may look like when it is raised to ground level.

Connection Point Examples

Maintaining your septic tank and its associated drains is important because it will save you time, money and help protect the health of your family and property. 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.

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

As the tank ages it may need to be replaced. Replacement of your septic tank requires wastewater works approval from Council. The septic tank and all other plumbing must be installed by a licensed plumber. The septic tank must be on the approved products list which can be found on the SA Health website.

Locate the connection point. It is typically located near the front or rear boundary of your property. If you have trouble locating the connection point, Council can provide some assistance to help you find it.

If there is no water flow observed through the connection point when you turn on a tap in your house, the blockage is most likely on your property. If this is the case, contact a licensed plumber to clear the blockage.

If water is holding at the connection point, the blockage is most likely in Council’s drain and you should call us on 8391 7200 so we can send someone from Council to assess and clear the blockage.

It is normal for your septic tank to appear full because of the design of the septic tank.

It is important to check that the plumber you are using is licensed. You can request to see their identification card which should contain their licence number. The licence number can then be checked using the Consumer and Business Services website

An unlicensed plumber may not undertake the required work correctly which may result in damage to your property and potentially impact any insurance claim or other warranties you may have.

Hahndorf is serviced by SA Water. You will need to contact SA Water (1300 650 950) for your service inquiries or a new connection.

Aston Hills subdivision is serviced by Alano Water. You will need to contact Alano Water (8240 2733) for your service inquiries or a new connection.

All other areas (Mount Barker, Nairne, Littlehampton, Brukunga, Meadows, Macclesfield and Echunga) are serviced by Council.

In general, Council will not approve the construction of any structure over or under any wastewater infrastructure. This is to ensure that Council has access to its infrastructure for maintenance and repair purposes.

If a property owner wishes to erect a demountable structure over a wastewater pipe, the applicant is encouraged to satisfy the following conditions:

  • The applicant must complete an indemnity form, where Council shall be indemnified against any damage to the structure as a result of any operations by council in exercising its rights under the Water Industry Act 2012 (to maintain, repair or upgrade wastewater infrastructure);
  • Council shall be reimbursed for any damage, repair or replacement of infrastructure required which is as a result of the erection of a structure;
  • Any hard standing area being installed over the wastewater pipe must be constructed of block pavers that are not mortared in position so they are capable of being removed to ensure access is maintained;
  • No earth filling or retaining that would obstruct, hinder or impede Council’s rights to access the infrastructure without approval from Council;
  • No removal/excavation of material from natural ground level is to occur where the level of excavation proposed will compromise the integrity of the infrastructure;

Vegetation to be planted within the area around infrastructure shall not compromise council’s ability to maintain infrastructure, or damage such infrastructure.

Yes you do. When a swimming pool is backwashed or emptied, the wastewater is generally pumped into the wastewater system main. The wastewater system network relies on gravity flows to drain wastewater from each of the connected properties and cannot manage pumped flows above 2L/s. A typical pool or spa connection to the property's internal wastewater drains should look like this:

Swimming Pool Discharge Diagram

Click image to enlarge

Wastewater from your pool or spa must bypass your septic tank and be discharged to the outlet drain between your septic tank and the wastewater system connection point.

You should plan to backwash or drain your pool or spa in off-peak times to avoid causing disruption to the wastewater system service for other residents. The best times for backwashing or draining are between 10:00pm and 6:00am for periods no longer than 30 minutes.

For additional information about disposing of wastewater from swimming pools or spas see the EPA website.

No, it isn’t. It is illegal to do so and residents must not allow any rainwater, stormwater or surface water to enter the wastewater system. You may get fined for illegal discharges.

If stormwater enters the wastewater system, the network can become seriously overloaded during and after rain events. When the wastewater system is overloaded, septic tanks cannot efficiently drain into the network and this appears as though the drain is blocked. In extreme cases, the wastewater system may overflow creating an environmental hazard.

The Mount Barker District Council is licensed by the Essential Services Commission of South Australia (ESCOSA) to operate as an intermediate water retailer under the Water Industry Act (WIA) 2012. Under the licence terms, Council is required to ensure service pricing covers the full cost of operations and maintenance of the system as well as full cost recovery of capital expenditure. Council has two wastewater charges, namely a CWMS charge as well as a sewer charge. The older CWMS areas with a septic tank are charged the CWMS charge while the new areas with a sewer connection are charged a sewer charge.

Note: On site systems not connected to the Council schemes are not charged an annual service fee and are outside the areas serviced by Council.

The wastewater annual service charge is based on the projected operational and maintenance costs as well as capital expenditure from Council’s Wastewater Asset Management Plan.

The annual service charge applies to properties connected to the wastewater system and is incorporated in your council rates bill.

Any wastewater charges collected by Council must be used to keep the system operational for current and future users of the system.  Some examples of wastewater related expenses include:

  1. The operation and maintenance of the wastewater system network;
  2. Renewal and upgrades of the wastewater system mains;
  3. Routine pump outs of septic tanks connected to the CWMS, and
  4. Treatment and recycling of wastewater

If you live in Hahndorf your property is connected to the SA Water Sewerage Network and would be charged a sewer fee by SA Water. This fee is calculated by SA Water and is based on a percentage of the CV of the property.

If you live in Aston Hills your property is connected to the Alano Water Sewerage Network and would be charged a sewer fee by Alano Water. This fee is calculated by Alano Water and is based on a percentage of the CV on the property.

Further information can be found at

Costs associated with wastewater services can be found in the Mount Barker District Council's Fees & Charges Register. Further information can be found on the fees and charges page.

Previously Council's system was known as Community Wastewater Management System (CWMS). It is now known simply as wastewater system. It incorporates the septic effluent collection systems from the old townships and the sewerage systems (without a septic tank pre-treatment) from the new growth areas.