Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
Sep. 30, 2025
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Risk Management and Strategy Risk Assessment Our cybersecurity policies, standards, processes and practices are integrated into our enterprise risk management processes and are based on a recognized framework established by the National Institute of Standards and Technology (“NIST”) and combined with the Center of Internet Security (“CIS”) controls framework are used to develop actionable steps for improving technical defenses and protecting against common threats. In general, we seek to address cybersecurity risks through a comprehensive, cross-functional approach that is focused on preserving the confidentiality, integrity and availability of the information that we collect and store by identifying, preventing and mitigating cybersecurity threats and effectively responding to cybersecurity incidents when they occur. We have established and maintain comprehensive incident response and recovery plans that detail our planned responses to cybersecurity incidents. These plans are tested and evaluated on a regular basis. We periodically assess and test the policies, standards, processes and practices that are designed to address cybersecurity threats and incidents. These efforts include a wide range of activities, including audits, assessments, tabletop exercises, threat modeling, vulnerability testing and other exercises focused on evaluating the effectiveness of our cybersecurity measures and planning. Independent Assessments We engage third parties to perform assessments of our cybersecurity programs, including information security maturity assessments, audits and independent reviews of our information security control environment and operating effectiveness. The results of such assessments, audits and reviews are reported to the Audit Committee and the Board of Directors, and we adjust our cybersecurity policies, standards, processes and practices as necessary based on the information provided by these assessments, audits and reviews. Technical Safeguards We deploy technical safeguards that are designed to protect our information systems from cybersecurity threats, including 24/7 detect and response services, network activity monitoring, phishing prevention, penetration testing and periodic IT security maturity assessments. As part of these efforts, we have engaged third-party cybersecurity providers to help deploy and monitor these safeguards and to assist in the event of a security incident or similar issue by conducting forensics reviews and assisting more broadly with the mitigation and remediation of any such event. Third-Party Risks We maintain a comprehensive, risk-based approach to identifying and overseeing cybersecurity risks presented by third parties, including vendors, service providers and other external users of our systems, as well as the systems of third parties that could adversely impact our business in the event of a cybersecurity incident affecting those third-party systems. Education and Awareness All employees are required to complete information security awareness training upon joining the Company. Based on individual phishing test performance and job requirements, additional training may be offered or required on an as-needed basis. Effects and Impacts of Cybersecurity Risks As announced on October 28, 2023, we identified a cybersecurity incident impacting certain internal operations and information technology systems which adversely affected our ability to ship orders in the first quarter of fiscal 2024. All of our facilities were operational by mid-December 2023 and were returned to normalized operations. We incurred $1.5 million of expenses related to the cybersecurity incident in the first fiscal quarter of fiscal 2024. Additionally, we have invested and intend to continue to invest in strengthening our systems, cybersecurity training, policies, programs, response plans and other similar measures. As of the date of this report, except as set forth herein, we are not aware of any risks from cybersecurity threats that have materially affected us, including our business strategy, results of operations or financial condition. See “Item 1A. RISK FACTORS” - “If we do not successfully maintain our information and technology networks, including the security of those networks, our operations could be disrupted and unanticipated increases in costs and/or decreases in sales could result,” “We may fail to effectively manage confidential data, which could harm our reputation, result in substantial additional costs and subject us to litigation,” and “Cyberattacks and security vulnerabilities could lead to reduced sales, increased costs, liability claims, unauthorized access to customer data or harm to our reputation.”
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	Our cybersecurity policies, standards, processes and practices are integrated into our enterprise risk management processes and are based on a recognized framework established by the National Institute of Standards and Technology (“NIST”) and combined with the Center of Internet Security (“CIS”) controls framework are used to develop actionable steps for improving technical defenses and protecting against common threats. In general, we seek to address cybersecurity risks through a comprehensive, cross-functional approach that is focused on preserving the confidentiality, integrity and availability of the information that we collect and store by identifying, preventing and mitigating cybersecurity threats and effectively responding to cybersecurity incidents when they occur. We have established and maintain comprehensive incident response and recovery plans that detail our planned responses to cybersecurity incidents. These plans are tested and evaluated on a regular basis. We periodically assess and test the policies, standards, processes and practices that are designed to address cybersecurity threats and incidents. These efforts include a wide range of activities, including audits, assessments, tabletop exercises, threat modeling, vulnerability testing and other exercises focused on evaluating the effectiveness of our cybersecurity measures and planning.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Our Board of Directors maintains oversight responsibility for how we manage risk, and it charges management with assessing and mitigating that risk through the development, implementation and maintenance of our risk management processes, including our cybersecurity program.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee of the Board of Directors oversees our cybersecurity and data privacy programs and practices and consults with management regarding cybersecurity initiatives. This committee is also responsible for reviewing cyber and data security matters, including cybersecurity threats that we may face in our operations and our risk mitigation initiatives.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	At least twice a year, the Audit Committee receives updates on our cybersecurity and data privacy programs and practices from our Senior Vice President of Information Technology and our Senior Director of Information Security.
Cybersecurity Risk Role of Management [Text Block]	Through ongoing communications with these teams, the Senior Vice President of Information Technology, the Senior Director of Information Security and the General Counsel monitor the prevention, detection, mitigation and remediation of cybersecurity threats and incidents in real time and report such threats and incidents to the Audit Committee when appropriate.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	Through ongoing communications with these teams, the Senior Vice President of Information Technology, the Senior Director of Information Security and the General Counsel monitor the prevention, detection, mitigation and remediation of cybersecurity threats and incidents in real time and report such threats and incidents to the Audit Committee when appropriate. Similarly, the Audit Committee reports cybersecurity threats and incidents to the full Board of Directors as appropriate.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our Senior Vice President of Information Technology holds an undergraduate degree in Technology Management (Manufacturing Systems), and has served in various roles in information technology for over 20 years and within Mueller for over five years. Our Senior Director of Information Security holds an undergraduate degree in Computer Engineering and has served in various roles in information security and engineering within Mueller for over 21 years.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	At least twice a year, the Audit Committee receives updates on our cybersecurity and data privacy programs and practices from our Senior Vice President of Information Technology and our Senior Director of Information Security. The topics reported by the Senior Vice President of Information Technology and our Senior Director of Information Security include updates on cybersecurity threats we face, the status of projects to strengthen our information security systems, assessments of the cybersecurity program, and the emerging threat landscape, as well as the results of any third-party assessments conducted.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Cybersecurity Risk Management and Strategy Disclosure

12 Months Ended

Sep. 30, 2025

Cybersecurity Risk Management, Strategy, and Governance [Line Items]

Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]

Risk Management and Strategy

Risk Assessment

Our cybersecurity policies, standards, processes and practices are integrated into our enterprise risk management processes and are based on a recognized framework established by the National Institute of Standards and Technology (“NIST”) and combined with the Center of Internet Security (“CIS”) controls framework are used to develop actionable steps for improving technical defenses and protecting against common threats. In general, we seek to address cybersecurity risks through a comprehensive, cross-functional approach that is focused on preserving the confidentiality, integrity and availability of the information that we collect and store by identifying, preventing and mitigating cybersecurity threats and effectively responding to cybersecurity incidents when they occur. We have established and maintain comprehensive incident response and recovery plans that detail our planned responses to cybersecurity incidents. These plans are tested and evaluated on a regular basis. We periodically assess and test the policies, standards, processes and practices that are designed to address cybersecurity threats and incidents. These efforts include a wide range of activities, including audits, assessments, tabletop exercises, threat modeling, vulnerability testing and other exercises focused on evaluating the effectiveness of our cybersecurity measures and planning.

Independent Assessments

We engage third parties to perform assessments of our cybersecurity programs, including information security maturity assessments, audits and independent reviews of our information security control environment and operating effectiveness. The results of such assessments, audits and reviews are reported to the Audit Committee and the Board of Directors, and we adjust our cybersecurity policies, standards, processes and practices as necessary based on the information provided by these assessments, audits and reviews.

Technical Safeguards

We deploy technical safeguards that are designed to protect our information systems from cybersecurity threats, including 24/7 detect and response services, network activity monitoring, phishing prevention, penetration testing and periodic IT security maturity assessments. As part of these efforts, we have engaged third-party cybersecurity providers to help deploy and monitor these safeguards and to assist in the event of a security incident or similar issue by conducting forensics reviews and assisting more broadly with the mitigation and remediation of any such event.

Third-Party Risks

We maintain a comprehensive, risk-based approach to identifying and overseeing cybersecurity risks presented by third parties, including vendors, service providers and other external users of our systems, as well as the systems of third parties that could adversely impact our business in the event of a cybersecurity incident affecting those third-party systems.

Education and Awareness

All employees are required to complete information security awareness training upon joining the Company. Based on individual phishing test performance and job requirements, additional training may be offered or required on an as-needed basis.

Effects and Impacts of Cybersecurity Risks

As announced on October 28, 2023, we identified a cybersecurity incident impacting certain internal operations and information technology systems which adversely affected our ability to ship orders in the first quarter of fiscal 2024. All of our facilities were operational by mid-December 2023 and were returned to normalized operations. We incurred $1.5 million of expenses related to the cybersecurity incident in the first fiscal quarter of fiscal 2024. Additionally, we have invested and intend to continue to invest in strengthening our systems, cybersecurity training, policies, programs, response plans and other similar measures. As of the date of this report, except as set forth herein, we are not aware of any risks from cybersecurity threats that have materially affected us, including our business strategy, results of operations or financial condition. See “Item 1A. RISK FACTORS” - “If we do not successfully maintain our information and technology networks, including the security of those networks, our operations could be disrupted and unanticipated increases in costs and/or decreases in sales could result,” “We may fail to effectively manage confidential data, which could harm our reputation, result in substantial additional costs and subject us to litigation,” and “Cyberattacks and security vulnerabilities could lead to reduced sales, increased costs, liability claims, unauthorized access to customer data or harm to our reputation.”

Cybersecurity Risk Management Processes Integrated [Flag]

true

Cybersecurity Risk Management Processes Integrated [Text Block]

Cybersecurity Risk Management Third Party Engaged [Flag]

true

Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]

true

Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]

false

Cybersecurity Risk Board of Directors Oversight [Text Block]

Our Board of Directors maintains oversight responsibility for how we manage risk, and it charges management with assessing and mitigating that risk through the development, implementation and maintenance of our risk management processes, including our cybersecurity program.

Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]

The Audit Committee of the Board of Directors oversees our cybersecurity and data privacy programs and practices and consults with management regarding cybersecurity initiatives. This committee is also responsible for reviewing cyber and data security matters, including cybersecurity threats that we may face in our operations and our risk mitigation initiatives.

Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]

Cybersecurity Risk Role of Management [Text Block]

Through ongoing communications with these teams, the Senior Vice President of Information Technology, the Senior Director of Information Security and the General Counsel monitor the prevention, detection, mitigation and remediation of cybersecurity threats and incidents in real time and report such threats and incidents to the Audit Committee when appropriate.

Cybersecurity Risk Management Positions or Committees Responsible [Flag]

true

Cybersecurity Risk Management Positions or Committees Responsible [Text Block]

Cybersecurity Risk Management Expertise of Management Responsible [Text Block]

Our Senior Vice President of Information Technology holds an undergraduate degree in Technology Management (Manufacturing Systems), and has served in various roles in information technology for over 20 years and within Mueller for over five years. Our Senior Director of Information Security holds an undergraduate degree in Computer Engineering and has served in various roles in information security and engineering within Mueller for over 21 years.

Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]

At least twice a year, the Audit Committee receives updates on our cybersecurity and data privacy programs and practices from our Senior Vice President of Information Technology and our Senior Director of Information Security. The topics reported by the Senior Vice President of Information Technology and our Senior Director of Information Security include updates on cybersecurity threats we face, the status of projects to strengthen our information security systems, assessments of the cybersecurity program, and the emerging threat landscape, as well as the results of any third-party assessments conducted.

Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]

true