Michigan does not actually have a “Form 420” for property tax protests. The form you’re looking for is Form 618 (L-4035), Petition to Board of Review, issued by the Michigan Department of Treasury under the General Property Tax Act.1Michigan Department of Treasury. Petition to Board of Review, Form 618 (L-4035) You use it to protest your property’s assessed value, taxable value, classification, or qualified agricultural property exemption, and you file it with your local city or township Board of Review during its March session. For 2026, that session begins Monday, March 9.2Michigan Department of Treasury. Key Dates for 2026 Boards of Review
What You Can Actually Protest
Form 618 covers four distinct challenges. You can raise one, or several, on the same petition by checking the relevant boxes near the top and filling in the matching numbered section below.
- Assessed value (Section 1). You believe the assessor set the value too high. Assessed value is supposed to equal 50 percent of true cash value (market value).
- Taxable value (Section 2). You believe the capped-value calculation is wrong — losses weren’t subtracted, additions were overstated, or the property was “uncapped” to full value after a transfer that should have been exempt.
- Classification (Section 3). You believe your property is in the wrong class (agricultural, commercial, developmental, industrial, residential, or timber-cutover). Classification affects which millage rates apply.3Michigan Legislature. Michigan Compiled Laws 211.34c
- Qualified agricultural property exemption (Section 4). The assessor denied or reduced your exemption from the 18 mills of local school operating tax for agricultural property.1Michigan Department of Treasury. Petition to Board of Review, Form 618 (L-4035)
One important boundary: the Board of Review has no authority over the homeowner’s principal residence exemption. That one is handled through a separate process with the assessor, not on Form 618.
Filling Out the Petition
You can download Form 618 from the Michigan Department of Treasury’s website or pick up a paper copy at your local assessor’s office.4Michigan Department of Treasury. Board of Review The form is two pages. Page one is yours; page two is reserved for the Board to record its decision.
Identifying Information at the Top
Fill in the owner’s name as it appears on the assessment roll, and the petitioner’s name if someone other than the owner is filing. Enter the township or city, county, and the year of appeal (2026).
The parcel code is the critical field. It’s the unique identifier for your property and is required. You’ll find it on your most recent assessment notice or tax bill. Property address and legal description are optional but worth including to prevent confusion.
Then check the box or boxes for each thing you’re protesting: assessed value, tentative taxable value, taxable status (exemption), classification, or qualified agricultural property exemption.
Section 1 — Assessed Value
Enter the current assessed value and your own estimate of the property’s true cash value. Because assessed value is supposed to be half of true cash value, if you believe your home is worth $300,000, your estimate of true cash value is $300,000 and you’re arguing the assessed value should be $150,000.
Section 2 — Taxable Value
Check the specific reason the taxable value is wrong: value of losses, value of additions, poverty exemption, or uncapping percentage. If your taxable value was reset after a transfer of ownership you believe qualified for an exemption (for example, certain transfers between family members through a trust under MCL 211.27a), this is where you say so.5Michigan Legislature. Michigan Compiled Laws 211.27a
One red flag worth checking before you file: if your taxable value jumped by more than the 2026 inflation rate multiplier of 2.7 percent, and you didn’t buy the property or add new construction, that’s a legitimate reason to protest.6State of Michigan. Inflation Rate Multiplier for 2026
Section 3 — Classification
Indicate what the assessor classified your property as and what you believe it should be. The Board must follow MCL 211.34c in deciding classification and cannot consider how a reclassification would affect your principal residence exemption or qualified agricultural property status.1Michigan Department of Treasury. Petition to Board of Review, Form 618 (L-4035)
Section 4 — Qualified Agricultural Property Exemption
Enter the percentage the assessor granted (or zero if denied) and the percentage you’re requesting.
Reason for Protest
Below the numbered sections is a space to explain why the assessment is wrong. Don’t just write “too high.” Give specifics: recent comparable sales suggesting a lower value, structural problems the assessor missed, an incorrect land measurement, or a transfer that shouldn’t have triggered uncapping. Write it so the Board can follow your reasoning without asking you to start over.
Sign, date, and provide your phone number and address at the bottom.
The Evidence That Actually Wins
The form itself is short. What decides your appeal is what you bring with it.
For an assessed-value protest, the strongest evidence is recent sales of comparable properties — homes similar in size, age, condition, and location that sold close to the December 31 tax day. Your assessor’s office keeps sales data, and county register of deeds records are public. Three comparable sales below your assessor’s figure give the Board something concrete to act on.
A professional appraisal from a licensed Michigan appraiser carries real weight, especially for properties with unusual features. Structural inspection reports documenting foundation damage, roof failure, or environmental contamination support a lower value. Dated photographs of the property’s condition make the case visual.
For taxable value protests, the evidence looks different. You’ll need to show the math — that the capped-value formula was applied incorrectly, that losses weren’t deducted, or that a transfer should have been exempt. Bring the relevant deed, trust documents, or other ownership records.
Deadlines and How to Submit
The 2026 March Board of Review begins Monday, March 9. Your local governing body may set an alternative start of Tuesday, March 10 or Wednesday, March 11, but it has to fall in that same week. The Board must meet at least 12 hours during the week, with its first meeting running at least 6 hours and starting between 9 a.m. and 3 p.m.7Michigan Legislature. Michigan Compiled Laws 211.30
Your assessment notice must be mailed at least 14 days before the Board meets, which gives you a narrow window to prepare. Call your local assessor’s office as soon as you receive the notice to confirm the exact schedule and submission requirements. Missing the March session typically means losing your right to protest the assessment for that tax year.
In Person, by Letter, or Through an Agent
You can appear before the Board in person to present your petition and evidence. If you’re a nonresident taxpayer, for example an out-of-state owner of Michigan rental property, you can file your protest by letter without appearing. Resident taxpayers can also file by letter, but only if the local city or township has adopted an ordinance or resolution allowing it; when it has, the option must be stated on your assessment notice and in the public notice of the Board meeting.7Michigan Legislature. Michigan Compiled Laws 211.30
An agent such as an attorney or tax consultant can appear and file for you. Some jurisdictions, including the City of Detroit, require a written Letter of Authorization from the property owner when an agent files.8City of Detroit. Letter of Authorization – Property Appeal Check with your assessor about whether a written authorization is required and whether a local form exists.
What Happens at the Hearing and After
Anyone who files a protest and appears, or whose agent appears, must be given an opportunity to be heard.7Michigan Legislature. Michigan Compiled Laws 211.30 This is your chance to walk the Board through your evidence: comparable sales, property defects, or an error in the taxable value calculation. Board members may ask questions. The local assessor often attends to defend the current figure.
The Board usually does not decide at the hearing. Every person who protested must be notified in writing no later than the first Monday in June. The notice states whether your assessment was sustained or changed, provides the adjusted figures if any, and explains your right to appeal to the Michigan Tax Tribunal, including the Tribunal’s address and filing deadlines.
If the Board Says No: Michigan Tax Tribunal
A Board of Review decision is not the end. If the Board denies your protest or doesn’t adjust the value as far as you believe is warranted, you can appeal to the Michigan Tax Tribunal, the state’s administrative tax court. You can e-file a petition through the Tribunal’s online system or print and mail a completed petition form.9State of Michigan. Small Claims – Michigan Tax Tribunal
Most residential owners file in the Small Claims Division, which uses an informal hearing process and no formal record, and most people represent themselves. The Small Claims Division cannot charge filing fees or costs on appeals involving principal residence property.10Michigan Legislature. Michigan Compiled Laws 205.749 Watch the deadline on your Board decision notice. The Tribunal enforces its filing dates strictly.
What the July and December Boards Can’t Do
Michigan law also requires Boards of Review to meet in July and December, but these sessions are not a second chance to argue valuation. They handle only qualified errors — clerical mistakes, incorrect calculations, or data entry problems the assessor has verified — along with specific exemption appeals like the disabled veterans exemption and the poverty exemption.11Michigan Legislature. Michigan Compiled Laws 211.53b If a qualified error produced an overpayment, a rebate with any interest must be issued. You cannot use the July or December session to reargue a valuation dispute the March Board decided. If you want to challenge your assessment, March is the window.