Regardless of the type of property, any waste water produced will need to be disposed of in an approved manner. Disposing of waste water other than rainwater in a stormwater drain is not permitted.

For most properties within the Nannup townsite, this will mean connecting to the Water Corporation’s reticulated sewerage system. In areas where reticulated sewerage is not available, onsite effluent disposal is required. To see if a property is connected, or can be connected to sewer, please contact the Water Corporation on 13 13 95. 

If sewer is not available, an approval to install an onsite effluent disposal system will be required. To obtain approval an application must be lodged with the Shire's Environmental Health Officer which will then be assessed and subject to approval conditions. 

Prior to any works taking place, it is a requirement that an application form be submitted to the Shire of Nannup, along with suitable plans and fee.

Onsite effluent disposal

In areas where reticulated sewerage is not available, onsite effluent disposal is required. Onsite effluent disposal refers to the treatment and discharge of waste water from properties onsite. Most effluent disposal systems used and installed are septic tanks and leach drains. The type and size of system will depend on a number of factors including the scale of development, volume of wastewater produced as well as environmental factors such as type of soil and proximity of water bodies or groundwater.

There are a number of different types of systems all with their own unique advantages and disadvantages. In some cases there may be restrictions on the type of system permitted usually due to environmental factors but in other cases it is a matter of personal preference. Regardless of the method ALL disposal and treatment systems must be made up of approved components. For more information, including what constitutes an approved system, please refer to the Department of Health.

Before an onsite effluent disposal system is installed, an application must be lodged with the Shire and approval obtained.

For applications for a single residence approval is obtained direct from the Shire. You will need to lodge an application form, which can be found at the link below, along with the required fees and supporting documentation. For commercial properties, an application for a second system on a property, or systems larger than 540L/day you will also require approval from the Department of Health. These applications are still lodged to the Shire however additional fees may apply. Once an application is received it will be assessed by the Environmental Health Officer to ensure the proposal complies with legislative requirements.

Application to Construct or Install an Apparatus for the Treatment of Sewage

Decommissioning existing systems

When sewer becomes available to a premises which has an onsite effluent disposal system, the owner has five years in which to disconnect the disposal system and connect to the sewer. When undertaking this work many people take the opportunity to decommission the onsite disposal system at the same time although this is not legally required.

Decommissioning of an onsite effluent disposal system is only required when –

  • There is a change in use of the premises, or 
  • The property is sold (within 60 days after change of ownership), or 
  • Extensions to the property encroach on set-back requirements for the system.

To decommission an apparatus you must –

  • Have the septic tanks emptied by a Licensed Liquid Waste Contractor and disposed of at an approved site. 

and either

  • Remove the septic tanks, leach drains or soak wells from site and backfill with clean compacted sand (this option is recommended particularly if property development is planned in the future).


  • Remove the septic tank, leach drain or soakwell lids and ensure the bottom of the septic tanks are broken up. Backfill the septic tanks, leach drains and soak wells with clean compacted sand.

Unfortunately once a system has been decommissioned it can be difficult to prove this fact. Therefore owners are encouraged to retain copies of any receipts and where possible take photos of the decommissioning work being undertaken for future reference.

Dealing with Problems from Waste Water


If the problem is with the Water Corporation’s sewer you can contact them on 13 13 75 to report the fault.


If the problem lies with the property's plumbing (on site disposal system or prior to sewer connection point) then the owner is responsible for undertaking repairs. They should engage the services of a licenced plumber to undertake any repairs.


Onsite effluent disposal systems will not function forever. Over time the soil surrounding the leach drains becomes clogged and saturated with fats which prevent it draining properly. If you have an old system which is not draining correctly your leach drains may need rejuvenating. To do this the existing soil surrounding the leach drains is removed and disposed of and new clean soil reinstated. Approval for this work is not required by the Shire unless the actual leach drains are going to be replaced.


Copies of plans may be available from the Shire however depending on the age of the property, this is not always the case or the quality of the information may be limited.  If the property is connected to sewer the Building Permit may show the plumbing lines. If there is an onsite disposal system then this will be shown in the septic approval. Contact the Shire on 9756 1018.


If you experience odour issues from a neighbouring property you should discuss the problem with them. If you are still unhappy you may report the issue to the Shire's Environmental Health Officer who will investigate the situation further. Please complete a General Request form and return it to the Shire office or by email to nannup@nannup.wa.gov.au.

General Request Form