The Five-Factor Test That Distinguishes a Local Government Fee From a Tax

In 1991, inside the Missouri Supreme Court chambers, justices handed down a ruling in Keller v. Marion County Ambulance District that would define municipal finance for decades. The court established a five-factor test to determine whether a local government charge is a legitimate user fee or an unconstitutional tax disguised as one. For property owners and local officials, this distinction dictates whether a new charge requires voter approval.[2][7]

The actionable takeaway for taxpayers and municipalities is that the label on the bill does not matter. A local government cannot bypass constitutional tax limits simply by calling a revenue-generating measure a "fee" or an "assessment." Instead, courts apply the five Keller criteria to examine the mechanics of the charge: when it is paid, who pays it, how the amount is calculated, and whether the service is a traditional government function.[1]

The legal foundation for this scrutiny stems from state-level tax and expenditure limitations, such as Missouri's 1980 Hancock Amendment. These constitutional provisions were designed to restrict the growth of state and local budgets by requiring a public referendum for any new tax. To prevent municipalities from circumventing the voters by simply renaming their taxes, the courts developed the five-factor framework to pierce the administrative terminology.[2][4]

The first factor examines the timing of the payment. As the Missouri Supreme Court articulated in its foundational ruling, "Fees subject to the Hancock Amendment are likely due to be paid on a periodic basis while fees not subject to the Hancock Amendment are likely due to be paid only on or after provision of a good or service to the individual paying the fee." In the 2002 case Merrill Larson v. City of Sullivan, a one-time connection charge for municipal utilities was upheld as a fee because it was assessed only when a property owner actually connected to the system, rather than as an annual recurring bill.[2][6]

The second factor asks who pays the charge. A true user fee is levied only on those who actually utilize the service. If a municipality blanket-bills all residents or property owners within its jurisdiction, courts are highly likely to classify the charge as a tax. This principle prevents local governments from spreading the cost of a specific service across the general tax base without securing voter consent.[1]

The third factor—whether the amount paid is affected by the level of goods or services provided—is often the pivot point in litigation. In the 1997 case Missouri Growth Association v. Metropolitan St. Louis Sewer District, the court upheld a sewer charge as a fee because it was based directly on a customer's metered water usage. If a customer used no water, they owed no fee.[1][7]

Conversely, flat rates applied uniformly regardless of consumption frequently fail this third test. When a local government charges every household an identical $50 monthly fee for a service, regardless of how much of that service the household actually consumes, the charge functions economically like a tax. Courts consistently reclassify these flat assessments as unconstitutional taxes if they were implemented without a public vote.[3][4]

The fourth factor evaluates the nature of the service itself, asking whether the fee relates to a service typically provided by the government. If a municipality is providing a proprietary service that private entities also offer—such as specific utility connections or specialized facility rentals—the charge is more likely to be recognized as a fee.[5]

The fifth factor looks at historical precedent, asking whether the activity has historically and exclusively been a government function. If the service is a core, exclusive government function like general policing or public administration, the charge leans heavily toward being a tax. The courts reason that core public goods should be funded through general taxation, not individualized user fees.[2][4]

These criteria are not applied with mathematical rigidity. Courts view the five factors as reliable indicators rather than absolute rules, weighing them together to determine the true nature of the charge. In the case Greg Wiley v. Gregory F.X. Daly, the court examined court costs imposed on delinquent taxpayers and determined that, because the primary purpose was to generate general revenue rather than compensate for a specific service, the charges operated as a tax and violated the state constitution.[2][3]

For local governments, the financial stakes of misclassifying a charge are severe. If a court determines that a purported fee is actually a tax levied without voter approval, the municipality may be forced to halt collection, refund years of collected revenues, and pay the plaintiffs' legal costs. A single misclassified utility charge can blow a multi-million-dollar hole in a city's annual budget.[4]

Consequently, municipal attorneys must rigorously stress-test any proposed fee increase against the five-factor framework before it ever appears on a resident's bill. The next time a local government announces a new "assessment" or "user charge," the legality of that bill will not depend on the press release, but on whether the charge scales with usage, targets only actual users, and avoids funding core government operations.[5][7]