On-site Sewage Management System Inspections

• On-Site Sewage Management Strategy 2021
• Local Government Act 1993
• Protection of the Environment Operations Act 1997
• AS/NZ Standard 1547 and 1546
• Environmental Planning and Assessment Act 1979

Commonly Asked Questions

What is an on-site sewage management system?

An on-site sewage management system (OSMS/OSSM), provides a means of disposing of human waste products from the toilet, bathroom and kitchen. Toilet waste is referred to as black water. Bathroom and kitchen waste is referred to as grey water.

The most commonly used design for an on-site sewage management system is demonstrated in the diagram below:

There are different designs of on-site sewage management systems available.

Primary Treated Systems are available as concrete and plastic septic tanks, grey water tanks and Aerated Wastewater Treatment Systems (AWTS). Primary systems do not treat black water/effluent. The effluent remains highly potent and requires disposal under the ground. For example in a trench, or evapo-transpiration area.

Secondary Treated Systems treat the effluent to a level that is safe to be dispersed through surface or subsurface irrigation.

Disposal areas for your on-site management system may be constructed as:

• Absorption trenches   
• Evapo-transpiration absorption (ETA) beds
• Sub surface irrigation >100mm below ground level
• Sub surface disposal >300mm below ground level
• Mound systems
• Surface irrigation (not be permitted for new systems on blocks less than 4000m2 in area or in sensitive locations.)

Consult with a wastewater specialist when choosing a new on-site sewage management system.

How does an on-site sewage management system work?

There are many various types of wastewater management systems and all work differently. Generally, wastewater (black and grey water) enter the septic tank and the solids settle over time. The effluent reaches the outlet of the system where it is either treated and/or disposed of in a disposal area.

Refer to NSW Health website for the different types of systems, or consult with your wastewater professional.

What maintenance will an on-site sewage system require?

Most systems require the sludge to be periodically pump-out. For example, a family of 4 people living in a house will require a pump out at least every 5 years. But do not wait until the system is full. When the sludge level reaches 2/3 full, engage a licenced pump-out professional and arrange for a tankers to pump-out your system. They will dispose of the waste appropriately.

It is important that you do not remove the sludge yourself, or apply it to land. This increases the risk of the spread of disease by bacteria, viruses, parasites and other organisms in the wastewater, contamination of groundwater and surface water, pollution of waterways, degradation of soil and vegetation and decreased community amenity, caused by odours, noise and insects.

Do I get charged for having an on-site sewage management system?

Council does charge for on-site sewage management systems. This fee is reflected on rates notices, and can be found at on Council’s website.

If you own an aerated wastewater treatment system (AWTS) you require quarterly services on your system to ensure they are working at optimal levels. Your service provider will charge a fee for service. That fee is determined by the service provider.

Why does Council inspect my on-site sewage management system?

All owners and operators of on-site sewage management systems require, under the Local Government Act 1993, a licence/approval to operate the system. In order to obtain such approval, the appropriate regulatory authority (Council) must be satisfied that the system complies with appropriate legislation and guidelines. Visit the Office of Local Government website for more information.

Why does Council inspect my on-site sewage management system when my service provider looks after it?

Only the appropriate regulatory authority (Council) is able to provide you with a licence/approval to operate an on-site sewage management system. The service providers are there to maintain the system, and ensure it is working efficiently.

How many times does Council inspect my on-site sewage management system?

All inspections are based on the risk-rating of your land and the on-site sewage management system condition. The table below provides a guide to determining the risk of a system. If the buffer distances are met, then the risk is low. If only one minor buffer distances has not been met, but all others have, then the risk is medium. If the majority of buffer distances have not been met then the risk is high.

*Environment & Health Protection Guidelines – On-site Sewage Management for Single Households (1998).

Inspections Schedule

• Risk Rating - Inspections conducted every
• Low - 5 years
• Medium - 2-3 years
• High - Annual

Why am I charged for having an on-site sewage management system?

Over the years on-site sewage management systems have created potentially hazardous and life-threatening environmental disasters. Waterways and drinking supplies have been compromised with septic material leaking into them. Spread of disease was high with the failure of septic storage systems, which lead government authorities to tighten regulations to better management such systems.

The costs associated with having an on-site sewage management system, charged by Council, allow Council, who are the appropriate regulatory authority, to conduct inspections and assess your on-site sewage management system. These inspections are based on compliance with associated legislation such as the Local Government Act 1993 and Protection of the Environment Operations Act 1997. Council staff require training, both prior to commencement of a position and ongoing, within appropriate regulatory areas. Administration duties are required to hold and maintain records, all of which is covered by the fees you are charged.

What does it cost?

Fees and charges for the current financial year are available on Council’s website, search for “On-site Sewer Management”.

What do I do if my on-site sewage management system is failing?

You should engage a suitably qualified and experienced person to assess your failing on-site sewage management system. It may be a simple fix. Council officers are always available to provide you with advice also. If your system is due for an licence/approval, then it will require an inspection, which is covered by your rates charges. If this is the case, then a Council officer will be able to assist in diagnosing the potential problem and inform you about how to have it fixed, before you spent thousands of unnecessary dollars.

How do I install a new on-site sewage management system?   

Steps to take when installing a new on-site sewage management system include:

1. Engage a licenced and experienced person to conduct the necessary works.
2. Submit a Section 68 application form to Council
3. Upon approval of the Section 68 application, works may commence.
4. Council will conduct several inspections throughout the install of your new system.

How do I modify my on-site sewage management system?

To modify your existing on-site sewage management system, which may include installing a new disposal area or a new septic tank, you should:

1. Engage a licenced and experienced person to conduct the necessary works.
2. Submit a Section 68 application form to Council
3. On the form this will be a Modification to the existing on-site sewage management system.
4. Upon approval of the Section 68 application, works may commence.
5. Upon completion, Council will inspect the modified on-site sewage management system area (tank/disposal area).
6. Upon satisfactory completion, an approval will be generated.