Mandurah area odours

Latest updates

Odour issues continue to affect communities around Mandurah. The department has taken regulatory action and remains committed to resolving the issue.

Three licensed premises in Nambeelup operate under the Environmental Protection Act and are required to manage odour emissions:

• C-Wise (L8410/2009/2) – liquid waste, compost manufacturing and soil blending. Licence expires 22 April 2028.
• CM Farms (L6932/1988/11) – intensive piggery. Licence expires 26 Oct 2029.
• Mushroom Exchange (L7210/1997/10) – compost manufacturing and soil blending. Licence expires 27 Apr 2026.

The department is engaging with the businesses on investigations and expert assessments to decide whether further regulatory actions are required to mitigate odour emissions from the precinct.

The department acknowledges the investigations have been lengthy, but the issue is very complex due to multiple odour sources and takes time to fully address. The department aims to keep the community informed through prompt and reliable updates to this community page. Please check here regularly for the latest news. 

C-Wise

The department is holding fortnightly meetings with C-Wise to establish an action plan to address odour emissions and to ensure progress is being made against the action plan.

C-Wise proactively reduced its waste acceptance during winter to support improved operations to mitigate odour risks.

The company has initiated independent investigations into its wastewater ponds and is compiling an emergency odour plan, prioritising the summer of 2025/26.

In addition, C-Wise has indicated a proposed change to the operational flow of its ponds, which will require its operating licence to be amended to facilitate the change.

C-Wise is also focusing on managing the quality of water in the dams to reduce potential off-site odour emissions. The company is preparing an accumulated sediment plan, which will provide guidance on how sediment and sludge from the facility will be managed immediately and in the future. This is likely to involve construction works to contain the sludge and minimise the odour while it is being processed.

Any change to current operations will be assessed by the department to ensure the changes are appropriate.

The department is currently working with C-Wise to finalise an amendment to their operating licence to incorporate infrastructure and operational improvements on the premises relating to odour management.  The amended licence will be issued in the coming weeks and once issued, will be available on the department’s website.

CM Farms

CM Farms has been in discussions with the department regarding operational improvements to be implemented to reduce the potential for off-site odours from their premises.  An amended licence was issued by the department on 13 November 2025 to incorporate these improvements as regulatory requirements.  The amended licence is aailable on the department’s website   Licences available for public appeal

Mushroom Exchange

Mushroom Exchange submitted an application to the department on 8 September 2025 for a licence amendment to replace two dam liners in their composting facility and to reposition groundwater monitoring bores. The amendment application will be advertised on the department’s website once accepted.
 

Across the precinct

The department recently engaged an independent consultant to collect samples across the Nambeelup precinct for a current analysis of all ponds and compost. The information obtained from the consultation is further assisting in the assessment and identification of areas for improvement to mitigate odours as summer approaches.

Following agreement at a meeting with community representatives and the department in July 2025, the department will be running an odour diary reporting program in Mandurah that will allow residents to log their odour experiences with greater detail. This program is expected to start in early November 2025 with a trained group of volunteers. The department is grateful to the community members who have volunteered to be involved in this program which will help us to verify the conditions contributing to odour impacts and monitor the effectiveness of improvements as they occur across the precinct.

Background

Throughout 2024 and 2025 to date, the department has received a high volume of odour complaints from residents in Secret Harbour, Mandurah, Singleton and Lakelands.

Following investigations which identified several businesses in Nambeelup as potential sources of these emissions, the department issued Environmental Protection Notices (EPNs) on 22 February 2024 to:

• WA Composts Pty Ltd (C-Wise) – C-Wise EPN (now completed and revoked).
• Derby Industries Pty Ltd (CM Farms) – CM Farms EPN.

Odour and wastewater experts were engaged to support ongoing assessments and recommend actions to reduce emissions.

On 25 October 2024, the department amended C-Wise’s licence to introduce stricter odour control conditions, including a requirement to develop a sludge management plan addressing odour, leachate and PFAS compliance.

The department again engaged an odour expert in late 2024 to better understand the odour emissions and inform further operational improvements.

Additional odour surveys were conducted in 2025 to assist the odour expert’s assessment, based on community complaints.

Working together

The department is grateful for community reporting of ongoing odour impacts, which supports the investigation and identification of odour sources. While some people may be weary of informing the department of the odour, the information is crucial to understanding the impact any changes to site operations may be having on community amenity.

Community members and residents are reminded that it is important to report odour impacts at the time odour is occurring by calling the Environment WAtch Hotline on 1300 784 782 or using the online reporting tool. Please be as specific as possible when describing the odour and its impact.

If you are concerned about your health, please see your doctor or call Health Direct on 1800 022 222 to discuss your symptoms.

We recognise and respect the right of individuals to express their views but we ask the community to respect the safety of our staff, contractors and visitors while we work to resolve these odour issues. We appreciate the community’s cooperation in maintaining a safe and constructive environment for everyone.

This page will be updated as new information becomes available. If you have any questions relating to this issue, please call the Environment WAtch Hotline on 1300 784 782.