The Michigan Plumbing Code Book: PA 733 vs. PA 230 Explained

Navigating the complex world of plumbing regulations in the Great Lakes State can feel like trying to fix a leak with duct tape—frustrating and likely to fail if you don’t have the right tools. Many homeowners, contractors, and even new inspectors often stumble when trying to understand The Michigan Plumbing Code Book PA 733 and PA 230, mistakenly treating them as the same document. In reality, confusing these two distinct legal frameworks can lead to failed inspections, hefty fines, or even unsafe installations. This guide will clear up the confusion, ensuring you know exactly which rulebook applies to your specific situation, whether you are laying pipe or applying for a license.

What Exactly Are PA 733 and PA 230?

To the untrained eye, Michigan’s plumbing laws look like a tangled mess of acronyms and numbers. However, understanding the distinction between Public Act 733 (PA 733) and Public Act 230 (PA 230) is the foundation of compliance.

• PA 230 (The Construction Code): This is the Stille-DeRossett-Hale Single State Construction Code Act. It governs the actual technical standards for building, including the adoption of the International Plumbing Code (IPC) with Michigan-specific amendments .
• PA 733 (The Licensing Act – Historical Context): Originally known as the State Plumbing Act of 2002, this act was created to regulate the people doing the work, not just the pipes . Crucially, PA 733 was repealed in 2017 and its provisions were moved into the Occupational Code under the Skilled Trades Regulation Act (PA 407 of 2016) .

Despite its repeal, you will still hear veterans in the industry refer to “PA 733” when discussing plumber licensing requirements because the core definitions and board structures originated there. Today, when people search for The Michigan Plumbing Code Book PA 733 and PA 230, they are usually looking for the intersection of who is allowed to work (formerly PA 733, now PA 407) and how the work must be done (PA 230).

Why the Confusion Persists

The terminology sticks around because the State Plumbing Board, originally created by PA 733, continues to exist and make recommendations under the new legislative framework . Furthermore, many older code books and online resources haven’t fully updated their language to reflect that licensing is now technically under PA 407, while the construction standards remain firmly under PA 230 .

PA 230: The Rulebook for Installation and Safety

If you are holding a wrench, PA 230 is your bible. This act empowers the state to adopt and enforce construction codes to ensure public safety, health, and welfare .

The Current Code Cycle (2026 Status)

As of March 2026, the active technical standard is the 2021 Michigan Plumbing Code, which became effective on March 12, 2024 . This code is based on the International Plumbing Code (IPC) 2021 but includes specific Michigan amendments found in “Part 7” of the administrative rules .

Key Components of PA 230 Enforcement:

• Adoption of Standards: It officially adopts the IPC with modifications tailored for Michigan’s climate and infrastructure needs .
• Local Enforcement: While it is a state code, PA 230 allows local units of government (cities, townships) to administer and enforce the code, provided they elect to do so .
• Scope: It covers everything from water supply distribution to sewage disposal systems in both residential and commercial buildings .

Expert Insight: According to the Bureau of Construction Codes, the purpose of PA 230 is to establish minimum requirements to safeguard life and property from potential dangers associated with plumbing systems .

The Evolution of PA 733: From Licensing Act to PA 407

This is where most people get tripped up. If you are looking for the “PA 733 Code Book” regarding licensing, you are technically looking for outdated information, although the spirit of the law remains.

The Repeal and Transition

In 2016, Michigan passed Public Act 407, known as the Skilled Trades Regulation Act. This legislation repealed the 2002 State Plumbing Act (PA 733) effective April 4, 2017 .

• Before 2017: PA 733 defined who could be a master plumber, journey plumber, or apprentice .
• After 2017: Those licensing requirements were transferred to Article 11 of the Occupational Code .

Why You Still Need to Know “PA 733” Concepts

Even though the act number changed, the requirements did not disappear. The State Plumbing Board, which was established by the original PA 733, continues to operate and oversee licensure . When professionals discuss The Michigan Plumbing Code Book PA 733 and PA 230, they are often referring to the dual requirement:

1. You must be licensed under the regulations formerly known as PA 733 (now PA 407).
2. You must install systems according to PA 230.

For example, Section 23a of PA 230 explicitly prohibits conspiring to circumvent the licensing requirements that originated from the PA 733 framework . This means you cannot legally perform plumbing work without the proper license, even if your installation perfectly meets the technical code.

Comparison: PA 230 vs. Former PA 733 (Current Licensing Rules)

To help you visualize the difference, here is a breakdown of how these two pillars of Michigan plumbing law interact.

Real-World Scenario

Imagine you are renovating a bathroom in Grand Rapids.

• PA 230 dictates that your new shower drain must have a 2-inch diameter pipe with a slope of 1/4 inch per foot.
• The Licensing Law (ex-PA 733) dictates that only a licensed Master Plumber or Journey Plumber can connect that drain to the main sewer line; a homeowner generally cannot do this specific task in Michigan without special affidavits that are strictly limited .

Step-by-Step: Ensuring Compliance with Both Acts

Whether you are a contractor or a homeowner managing a project, following these steps ensures you respect both the technical code and the licensing laws.

Step 1: Verify Licensure (The “PA 733” Legacy Check)

Before any work begins, confirm that the individual performing the plumbing is licensed.

• Check the licensee’s status on the Michigan LARA website.
• Ensure they hold the correct class of license (Residential Maintenance, Journey, or Master) for the scope of work .
• Note: Under the old PA 733 and current laws, a plumbing contractor must employ a Master Plumber to obtain a contractor’s license .

Step 2: Obtain the Correct Code Book

Do not rely on generic International Plumbing Codes. You must use the Michigan-specific version.

• Purchase or access the 2021 Michigan Plumbing Code, which includes the state amendments effective March 12, 2024 .
• Review “Part 7” of the Michigan Administrative Code for specific rule amendments that override the base IPC .

Step 3: Pull the Proper Permits

Permits are the bridge between PA 230 and licensing laws.

• Apply for a permit through your local municipality (city or township).
• The application will require the license number of the plumber performing the work, satisfying the licensing act requirements .
• Section 23a of PA 230 makes it illegal to conspire to bypass these permit and licensing requirements .

Step 4: Schedule Inspections

• Rough-in Inspection: Occurs after pipes are installed but before walls are closed. The inspector checks for compliance with PA 230 technical standards (slope, support, material).
• Final Inspection: Occurs after fixtures are installed. The inspector verifies the system is safe and functional.

Step 5: Testing and Certification

• Perform required pressure tests (usually air or water) as mandated by the Michigan Plumbing Code.
• Submit test reports to the inspector. For backflow preventers, specific test reports are mandatory under state rules .

Common Pitfalls to Avoid

Even experienced professionals can make mistakes when navigating these regulations.

1. Using the Wrong Code Edition: As of early 2026, some jurisdictions may still be transitioning. Always confirm if your local municipality is enforcing the 2021 code (effective March 2024) or if they have adopted a newer amendment . Using the 2015 or 2018 code for new permits in 2026 will result in a failed inspection.
2. Homeowner Exemptions Misunderstanding: Michigan is strict. While homeowners can do some work on their own primary residence, they cannot legally perform plumbing that requires a license unless they meet very specific affidavit requirements, and even then, major sewer connections often require a licensed professional .
3. Ignoring Local Amendments: PA 230 allows local enforcement agencies to adopt stricter rules. A city like Detroit or Ann Arbor might have additional ordinances on top of the state code . Always check with the local building department.

For a deeper dive into the history of construction codes and how states regulate industries, you can explore general regulatory frameworks on Wikipedia.

FAQ Section

1. Is PA 733 still the law for plumbers in Michigan?

No, PA 733 (The State Plumbing Act of 2002) was repealed effective April 4, 2017 . Its licensing provisions were transferred to the Skilled Trades Regulation Act (PA 407 of 2016). However, the term is still commonly used to refer to the licensing requirements for plumbers.

2. What is the current Michigan Plumbing Code book I need to buy?

As of March 2026, the current code is the 2021 Michigan Plumbing Code, which became effective on March 12, 2024 . Ensure you purchase the version that includes the Michigan-specific amendments (Part 7), not just the standard International Plumbing Code.

3. Can I do my own plumbing work in Michigan as a homeowner?

It is highly restricted. Michigan law generally requires plumbing work to be performed by licensed individuals (Master or Journey plumbers) . While some minor repairs or specific owner-occupier scenarios exist under affidavit, connecting to public sewers or major alterations typically mandates a licensed professional to comply with PA 230 and licensing laws .

4. What is the difference between the “Construction Code” and the “Plumbing Act”?

The Construction Code (PA 230) dictates how the plumbing system is built (pipe sizes, materials, venting). The Plumbing Act (formerly PA 733, now PA 407) dictates who is legally allowed to build it (licensing, training, and examinations) .

5. Who enforces these codes?

PA 230 is enforced by local building departments and municipal inspectors who verify the physical installation. The licensing aspects (formerly PA 733) are administered by the Department of Licensing and Regulatory Affairs (LARA) and the State Plumbing Board .

6. When will the next plumbing code update happen in Michigan?

Michigan typically updates its codes on a three-year cycle. Since the 2021 IPC-based code went into effect in March 2024, the next major update (likely based on the 2024 or 2027 IPC) would be expected around 2027, subject to legislative approval and rulemaking processes .

Conclusion

Understanding The Michigan Plumbing Code Book PA 733 and PA 230 is no longer about memorizing two active public act numbers, but rather grasping the vital relationship between technical standards and professional licensing. PA 230 remains the active authority on how plumbing systems must be designed and installed to ensure safety, while the legacy of PA 733 lives on through the strict licensing requirements now housed in PA 407.

By respecting both sides of this regulatory coin, you protect your investment, ensure the safety of your building’s occupants, and avoid the costly headaches of non-compliance. Whether you are a seasoned contractor or a DIY enthusiast, staying updated with the 2021 Michigan Plumbing Code and verifying licensure is the only way to build with confidence.

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