Apply to install or alter an on-site wastewater system

Step 1 - Complete the application form 

Complete the Application to Construct or Install an Apparatus for the Treatment of Sewage Form (PDF 687KB)

It is recommended this form is completed by a registered plumber or builder on behalf of a property owner who has knowledge of the system. You can also contact your local government Environmental Health Services to discuss what system is best suited to your area.

If you are the property owner, it is your responsibility to discuss the requirements with your plumber or builder before submitting your application to ensure the information is accurate and complete.

All required information must be submitted with the application, otherwise this may delay the overall assessment and approval time for your application.

Assessment of applications that are submitted to the Department of Health will only begin once all required information is submitted.  

Make sure you:

1. complete sections 1-8 of the application form (PDF 687KB) in full
2. ensure plans are submitted according to the specifications detailed in section 7 of the application form. Hand drawn plans are not accepted
3. ensure relevant application fees detailed in Appendix 2 of the form are paid
4. ensure all relevant information is submitted
5. Check the system is approved for use in WA. Only approved systems will be accepted

If you need assistance, contact your local government’s Environmental Health Officer.

Step 2- Lodge the application form with the relevant local government

All completed application forms MUST be submitted directly to the local government Environmental Health Services where the system is proposed to be installed, altered, extended or upgraded.

Check with your local government regarding their application submission process. Refer to the local government directory (external site) for contact details.

All applications MUST be submitted to the local government Environmental Health Services in the first instance for assessment.

However, the agency who provides final approval will depend on the daily volume of wastewater and the type of premises.

You can view the Wastewater application flowchart (PDF 350KB) for an overview of the process and who will approve your application.

Firstly, check approved wastewater systems to make sure the product you intend to install has been approved for use in WA. If it is not on the list, it cannot be used.

Essential information that must be included with your application:

1. A copy of plan and specifications of the proposed apparatus showing the top and longitudinal section to a scale of not less than 1:50.
2. One copy of a site plan of the premises to a scale not less than 1:100, showing:

• the position of all buildings erected or proposed and the position of the proposed and any existing apparatus including setback distances
• the position, type and proposed use of all fixtures intended to discharge into the apparatus
• the position and setback distances of all drains, pipes, inspection openings, vents, traps and junctions in relation to buildings and boundaries
• the size of pipes and fittings and the fall of the drains
• details of the proposed and any existing effluent disposal system and its setback distances to buildings, boundaries and trafficable areas; and
• the source of water supply to be used in connection with the apparatus if premises is not supplied by a non-reticulated mains supply

Note: Hand drawn plans will not be accepted.

Other key documents that are required for specific applications:

1. Site and soil evaluation report (for development assessments)

   A site and soil evaluation may be requested at the development assessment stage by your local government.
   Individual landowners or developers are responsible for engaging a suitably qualified and experienced professional to undertake a site and soil evaluation for unsewered developments and subdivisions. 

   Refer to site and soil evaluation for more information.

2. Signed certified engineering specification (only for systems above 540 litres)

   Certification for all onsite wastewater treatment systems against the relevant Australian Standard must be submitted with the application, but only for systems above specified volumes. Individual landowners or developers are responsible for engaging a suitably qualified Australian engineer to provide an engineering certificate or in many cases obtaining a certificate directly from the product manufacturer.

   Refer to certification for installation of wastewater treatment systems for more information. 

3. Signed maintenance agreement for onsite wastewater treatment system 

   A primary treatment system needs to be pumped out every 4 years or more often according to the installation approval conditions. 

   A secondary treatment system requires a signed maintenance contract / agreement from an authorised service person stating that the apparatus will be maintained and serviced.

   Refer to servicing wastewater systems for more information.

If your site is not a single dwelling (e.g. commercial / multi dwelling sites) and produces more than 540 litres of sewage per day the following information needs to be submitted as part of your application:

Nature of the project

Provide details of the proposed project including:

• type of the development
• description of staged development, if planned
• size of served facility
• intended use of the building and the intended use of rooms within the building
• proposed installation and methods of disposal/reuse of the final effluent.

Site and soil evaluation

Individual landowners or developers are responsible for engaging a suitably qualified and experienced professional to undertake a site and soil evaluation for unsewered developments and subdivisions.

A qualified professional should have tertiary qualifications in soil sciences, hydrology, engineering, or similar.

A site and soil evaluation should be carried out in accordance with AS/NZS 1547: 2012 On-site domestic wastewater management. Refer to further guidance on site and soil evaluation, including the:

• Guidance on Site-and-soil evaluation for on-site wastewater management (PDF 360KB) outlining general requirements for SSE
• Template for Site and Soil Evaluation Report (Word 983KB) with detailed information and guidance for each section

Plans and specifications

A detailed plan of the on-site wastewater system, site plan and a building plan must be submitted. All plans are to be drawn to a scale of not less than 1:100.

Below is an example image of a site plan. Please note hand drawn plans will not be accepted. 

System plan

System plans submitted for consideration must:

• show dimensions
• be accompanied by a list of all components
• show the intended layout of the system including the typical sittings of:
  • tanks
  • chambers and control panels
  • pipes
  • inlet and outlet arrangements
  • effluent application areas or discharge points

• show the capacities of all system components
• any other relevant details.

Site plan and building plan

A site plan must clearly show

• the location of all:
  • buildings or proposed buildings
  • water tanks
  • swimming pools
  • driveways
  • excavations
  • storm water drains
  • water pipes
  • easement drains
  • streams
  • water courses
• details of any site modifications for example:
  • benching
  • cutting
  • filling
• site boundaries and size of the lot including dimensions in metres or millimetres
• key topographical features for example:
• creek line
  • drainage line
  • slope of the land
  • direction of flow of storm water
  • flood plains
• distances from boundaries, watercourses, buildings to the existing and proposed on-site wastewater treatment and disposal systems
• exact location of all fixtures and fittings.

Design details of the system

• type of system
• trade name, if any
• manufacturer's name
• design capacity of the system.

Note: The proposed treatment and disposal systems must be approved by the Department. It is important to check that the product you intend to install has been approved for use before submitting an application

Description of treatment process

If the system exceeds the volumes of 6000L/day (septic), 5000L/day (secondary treatment system) then engineering certification must be submitted.

Flow and load of effluent

Details must be provided of the sewage generating development including:

• maximum number of persons using the system/occupancy rate
• type of facility to be served and per capita daily wastewater flow rate
• total hydraulic load
• calculation of daily wastewater volume
• composition of wastewater for example
  • blackwater
  • greywater
  • non-domestic characteristics.

Effluent quality

Effluent that is to be of secondary quality, in accordance with AS/NZS 1547, shall meet the effluent compliance criteria detailed in AS/NZS 1546.3.

Quality of effluent after treatment should be meet the system shall be demonstrated prior to land application or discharge in terms of the following characteristics:

• biochemical oxygen demand (BOD)
• suspended solids
• free residual chlorine
• faecal coliforms
•  pH
• grease or oil

Land application 

Treated wastewater can be reused or simply disposed of depending on the type of land application system that is used and the quality of effluent. The disposal of the wastewater can be through:

• a soil absorption system for example:
  • leach drains
  • soak wells

• an irrigation system which is located on a dedicated disposal area (not for beneficial use)
  • subsurface
  • surface irrigation.

Signed maintenance agreement

A signed maintenance agreement between the owner and the service provider must be submitted for ongoing servicing, pump out and emergency repairs.

Regular maintenance of any systems must be detailed in the maintenance agreement including frequency of maintenance and methods.

The property owner will be held responsible for the ongoing operation of the system and should make any tenant aware of their responsibilities.

Refer to servicing wastewater systems for more information.

Note - this requirement does not apply to conventional septic tank systems.

Certified engineering specification

Refer to certification for installation of wastewater treatment systems for information on which systems are required  

Certified engineering specification of commercial wastewater treatment plants and treatment ponds must accompany applications where these are proposed.

Individual landowners or developers are responsible for engaging a suitably qualified Australian engineer to provide an engineering certificate or in many cases obtaining a certificate directly from the product manufacturer.

An ancillary dwelling (commonly known as a granny flat) is a dwelling for people who live either independently or semi dependently to the resident of the single house on the same lot, sharing some site facilities and services.

An ancillary dwelling must have planning and building approval from the Local Government and must meet the Department of Planning requirements.

An ancillary dwelling can either:

1. Connect to an existing onsite wastewater system serving the main house or
2. Install a separate onsite wastewater system.

Sizing wastewater systems servicing for ancillary dwellings

Where an ancillary dwelling is to be connected to the existing onsite wastewater system the following applies:

• Wastewater loading will be calculated on the combined hydraulic loading based on the total combined number of bedrooms (ancillary dwelling PLUS main residential dwelling) and sized as a "Standard Residential dwelling" applying the following formula - Wastewater loading (L/day): Number of occupants (persons/day) x 150L/person/day
• The Local Government Environmental Health Officer (EHO) will determine the combined occupancy rates for both the main house and ancillary dwelling.
• The receptacle for drainage shall be sized using the wastewater loading determined with the formula above. 
• Septic tanks shall be sized according to Regulation 28 of the Health (Treatment of Sewage and Disposal of Effluent and Liquid Waste) Regulations 1974 (Regulations).
• The EHO must be notified to determine if the existing system is sufficiently sized and if an upgrade to the system is required prior to connection.

Examples:

• 3 bedroom main dwelling PLUS 2 bedroom ancillary accommodation = 5 bedroom system (829L/day)
• 4 bedroom main dwelling PLUS 2 bedroom ancillary accommodation = 6 bedroom system (150L/person/day).

Where an ancillary dwelling has its own separate system, the system shall be sized according to the Regulations as a residential dwelling.

Local government approval

If the combined occupancy of the main house and ancillary dwelling is less than or equal to 8 persons, the wastewater system serving the ancillary dwelling (either combined or separate) can be approved by local government.

Department of Health approval

When the combined occupancy of a single dwelling and the ancillary dwelling exceeds 8 persons, the alteration, construction and installation of the wastewater system will require approval by the Chief Health Officer (Department of Health).

When an ancillary dwelling becomes a separate dwelling to the main house

An ancillary dwelling becomes a separate dwelling when the land is subdivided and the ancillary dwelling is located on a separate lot to the main dwelling.

If this occurs both dwellings will require their own separate onsite wastewater system that complies with regulations.

A tiny home (with or without wheels) is a habitable dwelling that are smaller than typical residential ancillary dwellings and may be pre-fabricated for placement on a site.

All habitable dwellings must have a wastewater system approved by the local government. An onsite wastewater application must be submitted.

Refer to the Western Australian Planning Commission (WAPC) Tiny House Fact Sheet (external site) for more information. 

A site and soil evaluation will be requested at the development assessment stage by your local government.

Checking soil type and site conditions is a critical step of the application process for certain sites.

If the site and soil is not suitable and the wrong system is proposed you may experience system failures, costly repairs and cause public health and environmental risks.

In general, you will be required to submit a site and soil evaluation report if your site:

• is located near a sensitive water resource area e.g. dams, rivers, estuaries, drinking water catchment areas
• may have soil constraints e.g. clay soils, high water tables, flood prone land, impermeable soil stratification, sloping land
• has site sizing constraints e.g. small lot size

A site and soil evaluation report is generally not required for proposals where:

• the site has had prior approval or the soil type is well known e.g. coastal sandy area
• the site does not require a development assessment
• low risk applications / homogenous environments e.g. no clear sensitivities and treating low volumes of waste

Site and soil evaluation report

Individual landowners or developers are responsible for engaging a suitably qualified and experienced professional to undertake a site and soil evaluation for unsewered developments and subdivisions.

Refer to the site and soil evaluation for detailed guidance on information that must be submitted as part of the site and soil evaluation assessment.

The aim is to:

• assess the capacity of the site to sustainably manage sewage within lot boundaries
• identify public and environmental health risks of on-site wastewater management especially the effect on groundwater and surface water on the site
• identify the most appropriate on-site system in consideration of site conditions and the nature of the proposed development and
• identify and implement a management program to minimise these risks if required.

Wastewater can also be reused with appropriate treatment to the required standards and some management controls for a wide range of beneficial uses including:

• industrial uses for example
  • cooling
  • dust suppression.

• non-industrial uses for example
  • irrigation of public open spaces and agriculture
  • toilet flushing.

Any reuse of wastewater must be in accordance with the non-potable uses of recycled water guidelines.

All recycled water schemes must be approved by the Department of Health prior to implementation. A separate application must be submitted for the reuse of wastewater.

When the wastewater reuse, disposal or combination of both is proposed the following details of the land application area must be submitted:

• Type of land application system for example:
  • surface
  • subsurface
  • evaporation pond
  • leach drains.

• Reason for selection and suitability of type of land application.
• Sizing of land application area.
• Layout of land application area.

You may need to pay one or two fee payments depending on the size and complexity of the system.

Local government application fee (paid to local government)

Once your application is submitted to the local government, a local government officer will make contact with the applicant to arrange payment of the applicable fees and any further information required prior to assessing.

If you need to discuss payment contact your local government (external site).

Department of Health application fee

In addition to a local government application fee, if the application needs to be submitted to the Department of Health an applicant will:

• be provided a reference ID number that must be used when referring to the application and paying fees
• be emailed fee payment instructions within 1- 3 business days of submitting an application

An application will not be processed until payment is received and all required information submitted.

If you have not received fee payment instructions within 5 business days email wwapps@health.wa.gov.au with your reference ID number in the subject line.

Wastewater application fees

Application fees are set as per the Health (Treatment of Sewage and Disposal of Effluent and Liquid Waste) Regulations 1974 (external site) Schedule 1.

Important note for applicants 

* You may apply to the Chief Health Officer without a local government report if your local government has not assessed your application within 28 days. 

Products approved for use in WA

Check approved wastewater systems to make sure the product you intend to install has been approved for use in WA.

Calculating hydraulic load 

Hydraulic load = how much wastewater the soil has to handle.

It’s usually based on daily water use (for example, litres per day from a household). Soil can only absorb and disperse a certain amount of water at a time. 

To calculate what size system you need refer to calculating the hydraulic loading for wastewater systems.

The hydraulic loading is based on Schedule 9 of the Health (Treatment of Sewage and Disposal of Effluent and Liquid Waste) Regulations 1974.

Wastewater calculator 

Once you have determined the hydraulic load you may use the Wastewater Calculator (Excel 500KB) to assist with determining the size requirements of a system. It is essential that the hydraulic load is correct otherwise the calculator will not be accurate. 

The following guidelines will assist with completing your wastewater application.

• Approved wastewater systems
• Wastewater system loading rates
• Wastewater calculator (Excel 500KB) 
• Site and soil evaluation for onsite wastewater management
• Certification for installation of wastewater treatment systems
• Independent third party engineering verification

When is an application required?

On-site disposal of wastewater is required in areas where reticulated sewerage is not available. An application must be lodged every time you intend to construct, install, alter, extend or upgrade an apparatus for on-site wastewater disposal. All applications must be lodged to the local government in the first instance.

The local government will process your application if the proposed apparatus will treat less than 540 L/day of wastewater or the building to be serviced is a single dwelling.

If the wastewater volume received by the system is more than 540L/day and the building being serviced is not a single dwelling the local government will assess your application and prepare a local government report. The report and application will be forwarded to the Department of Health for processing by the local government.

How long will it take to process your application?

The time taken to complete an application will depend on the size and complexity and whether all relevant information has been received.

Applications that require local government approval only

Processing times may vary depending on the local government. It is recommended you discuss this with your local government environmental health services. By law local governments are obliged to process applications “as soon as practicable after receiving the application”.

Applicants that require local government and Department of Health approval

If an application requires Department of Health approval, an additional 60 to 90 business days, in addition to local government processing times will be required for the Department of Health to assess your application. The processing timeframe begins once the Department of Health receives a complete application with all required documentation. 

The Department of Health has recently experienced an influx of wastewater applications which has resulted in longer processing times than usual. 

All submissions are assessed in the order they are received. There is no process available to expedite or prioritise individual applications.

Can I track progress of my application? 

There is no online tracking system available. Once the application has been allocated, the assigned officer will make direct contact with the applicant to provide updates or request any further information if required. 

What are the fees?

Refer to the section above for more information about fees. Note that local government fees and Department of Health fees are processed separately.

What if I forgot to attach or include relevant information to my application?

Assessment of the application will not commence until the outstanding information is provided. If you need to provide additional documents or information to support your application, please email to wwapps@health.wa.gov.au and include the application reference ID number in the subject line. 

Content of the email has a maximum limit of 20MB per email.

Can I change the plan after I have lodged the application?

Significant changes to any of the treatment, site, hydraulic loading or disposal characteristics will require a new application.

Small variations to disposal plans are acceptable if they can be supported by a site and soil evaluation report.

You are encouraged to contact your local government prior to considering any changes

What if my application does not comply?

If your application does not comply then you will receive a letter of refusal stating the reasons why we cannot approve your application to construct or alter an apparatus.

Can I cancel my application if I change my mind?

Yes, you can cancel your application at any stage. Email your local government. Alternatively, for applications that require Department of Health approval email wwapps@health.wa.gov.au

Can I get a refund on the application fee if I cancel?

You must contact your local government about fee refunds for local government applications.

Applications submitted to the Department of Health will be returned and refunded. Email wwapps@health.wa.gov.au for refund requests.

A refund is not provided for applications that do not receive approval form the Department of Health Chief Health Officer, or if the technical officer has commenced the assessment of the application

Can I get a copy of the application details that were submitted?

Once the application is received, the applicant will receive a confirmation email with the application ID reference number.

Can I construct or install a wastewater system before I get an approval?

No. It is an offence to commence construction or installation of any wastewater system without an approval from either the local government or the Department.

Can I use a wastewater system before it is approved?

No. Before you can use any wastewater apparatus, the local government must inspect the system to ensure it is installed correctly.

If the installation is satisfactory, the local government will issue a permit to use.

It is an offence to use the system prior to receiving the permit to use.

Will an approval or a permit be given if I have used the wastewater system?

No. There is no provision in the legislation to provide a retrospective approval. It is possible that you may be directed to stop using and remove the apparatus.