St. Louis County Property Tax Appeal: Grounds, Evidence, and Hearing

If you want to challenge your assessment, a St. Louis County property tax appeal is filed with the county Board of Equalization between May 1 and the second Monday in July. The county reassesses all real property in odd-numbered years, so the next full reassessment cycle lands in 2025. One detail worth knowing before you start: in St. Louis County, Missouri law puts the burden of proof on the Assessor, not on you. The process is designed to be handled without an attorney.

When to File and How to Submit

The appeal window opens May 1 and closes on the second Monday in July.¹ Miss it and you lose the right to contest your assessment for that tax year. If a reassessment changed your value, the county mails a Change of Assessment Notice; that notice is your signal the appeal clock is running.

St. Louis County accepts filings three ways:

Online through the county’s SmartFile portal, which lets you upload the form and supporting documents and gives you immediate confirmation.
By mail to the Board of Equalization office in Clayton. Certified mail gives you proof of delivery.
In person at the Board of Equalization office.

The form asks for your property’s locator number, which appears on your tax bill, and your opinion of value: the specific dollar amount you believe the property is worth. That figure needs to line up with the evidence you plan to present. A number pulled out of the air will not hold up at a hearing. Gather your documentation before the deadline, because you cannot add new evidence after the appeal window closes.¹

Grounds You Can Raise

Missouri recognizes three grounds for challenging an assessment: overvaluation, unequal assessment, and misclassification. One is enough, though some owners raise more than one in a single appeal.

Overvaluation is the most common. State law requires assessors to value real property at its true value in money, which effectively means fair market value.² If your home is assessed at $350,000 and comparable homes sell for $300,000, that gap is your argument.

Unequal assessment is a uniformity argument. Even if your value is within market range, you can show that comparable properties on your block are assessed significantly lower. Two near-identical houses with a $40,000 difference in assessed value is the classic example.

Misclassification happens when the Assessor puts your property in the wrong category. Residential property is assessed at 19 percent of true value, agricultural at 12 percent, and commercial or other at 32 percent.³ A home classified as commercial is being taxed at nearly double the correct rate. These appeals are less common but produce the largest tax savings when they succeed.

The Burden of Proof Is on the Assessor

Many homeowners do not realize this: in St. Louis County, there is no presumption that the Assessor’s valuation is correct. Under RSMo 138.060, in any county with a charter form of government and more than one million residents, the assessor must prove the valuation does not exceed true market value.⁴ St. Louis County fits that description.

The statute goes further. If the Assessor used a computer-assisted method, and most valuations in the county are computer-assisted, the valuation must be supported by clear, convincing, and cogent evidence.² If a required physical inspection was not performed properly, you win as a matter of law.⁴ Filing is not a long shot. Bring reasonable evidence, and you are in a strong position.

Evidence That Carries Weight

Even with the burden on the Assessor, the hearing officer needs something concrete to settle on a corrected value. Four kinds of evidence do most of the work.

Recent comparable sales. Three to five sales of similar homes nearby, within the last year or two, matched to yours on size, age, condition, and location.
A licensed appraiser’s opinion of value. Not required, but useful when your property has unusual features that make comparables hard to find.
Photos documenting condition. Foundation cracks, roof damage, outdated systems, and deferred maintenance all reduce market value, and the Assessor may not have accounted for them.
Written repair estimates from licensed contractors. A $25,000 roof or $15,000 foundation repair gives the hearing officer a specific number to weigh.

What Happens at the Hearing

After you file, the Board schedules a hearing. You or your representative appears before a hearing officer and presents your evidence. Someone from the Assessor’s office appears as well and defends the valuation. The format is relatively informal, and most homeowners handle it themselves without a lawyer.

One procedural limit works in your favor: the Assessor’s office cannot argue for a value higher than what the Assessor originally determined or the Board’s value, whichever is higher.⁴ The government can defend its number but cannot suddenly claim your property is worth even more. The written decision usually arrives within a few weeks of the hearing.

Keep Paying Your Tax Bill

Filing an appeal does not pause your tax obligation. Missouri property taxes are due by December 31, and interest and penalties apply if you miss that date whether or not an appeal is pending. You can file an appeal even if you have not yet paid.⁵ If the appeal succeeds and your value is reduced, the county adjusts your liability and you get a refund or credit. Pay the full amount by December 31 to avoid penalties and treat a win as money coming back later.

If the Board Rules Against You

The next step is the State Tax Commission of Missouri. You must file by September 30 or within 30 days of the Board’s written decision, whichever is later.⁶ The Commission has no authority to extend these deadlines for any reason.⁷

Two narrow exceptions apply: when the property was purchased within 30 days of the Board’s deadline or after it in the same tax year, and when the owner never received an assessment increase notice at least 30 days before the Board’s deadline.⁷

STC proceedings are more formal than the county hearing. Individual owners can represent themselves, but trusts, corporations, LLCs, partnerships, and other legal entities must be represented by an attorney.⁷

Appeals in Even Years

Reassessment is an odd-year event, but you are not locked out in even years. Missouri allows a real property appeal in an even-numbered year if you did not appeal the previous year, and a successful even-year appeal affects only that year’s assessment.⁷ That option matters if you missed the odd-year deadline or if the market shifted after reassessment.

1
St. Louis County SmartFile. St. Louis County Property Appeal Form
2
Missouri Revisor of Statutes. Missouri Code 137.115 – Real and Personal Property, Assessment
3
Missouri State Tax Commission. State Tax Commission Definitions
4
Missouri Revisor of Statutes. Missouri Code 138.060 – Appeals From Assessors Valuation, Burden of Proof in Certain Counties
5
State Tax Commission of Missouri. Paying Property Taxes Under Protest And/Or Appeal Options
6
Missouri Revisor of Statutes. Missouri Code 138.430 – Appeal to State Tax Commission
7
State Tax Commission of Missouri. Property Tax Appeals Before The State Tax Commission of Missouri