Cloudy With a Chance of Mandamus: Illinois Courts Split on Solar Siting

Local governments hoping for a clear forecast on commercial solar development recently received two very different opinions from the Illinois Appellate Court.

In March, the Third District held that once a commercial solar applicant satisfies the requirements authorized by Illinois law, the county must approve the application. Three months later, the Fourth District held that counties may still apply traditional special use standards and exercise discretion in deciding whether a solar project belongs in a particular location.

The disagreement affects more than county zoning boards. Solar projects in unincorporated areas can directly affect township roads, drainage systems, culverts, intersections and emergency access. The decisions therefore provide important guidance for townships and road districts participating in the approval process.

The Statutory Question

In 2023, the General Assembly substantially amended section 5-12020 of the Counties Code to create statewide standards for commercial wind and solar facilities.

The law restricts counties from imposing requirements more stringent than those permitted by the statute. It also provides that a request for siting approval or a special use permit “shall be approved” if it complies with the Counties Code, a lawful local zoning ordinance and applicable state and federal requirements.

At the same time, the statute continues to call the approval a “special use permit” and requires a public hearing at which evidence may be presented and witnesses may be questioned.

That creates the central question. Is the hearing limited to determining whether the developer checked the required boxes, or may the county still decide that a technically compliant facility is inappropriate at the proposed location?

Equity Solar: Approval Becomes Mandatory

In Equity Solar Illinois v. County of Grundy, 2026 IL App (3d) 250289, developers sought special use permits for two commercial solar facilities in unincorporated Grundy County.

No one disputed that the applications satisfied the applicable technical requirements. Following public hearings, however, the County denied them based on concerns involving compatibility with surrounding property, safety, future development, airport expansion and possible battery storage.

The developers sought mandamus and asked the court to compel the County to issue the permits. Mandamus is an extraordinary remedy used to require a public official or governmental body to perform a clear, purely ministerial duty. It generally cannot be used to control how a governmental body exercises judgment or discretion.

The Third District affirmed an order requiring the County to issue the permits. Although the court recognized that the statute did not eliminate all local discretion, it concluded that discretion was limited to establishing and enforcing conditions permitted by the statute. Once a developer satisfied those lawful conditions, the direction that the permit “shall be approved” became mandatory.

The defense warning from Equity Solar is significant. Generalized concerns about community opposition, future development or whether a project is desirable may not support denial unless those concerns are tied to a lawful ordinance provision or authorized condition.

Tate Road Solar: Some Discretion Remains

The Fourth District reached a different conclusion in Tate Road Solar 1, LLC v. County of Winnebago, 2026 IL App (4th) 250873.

Winnebago County’s ordinance incorporated the statewide requirements but also allowed consideration of traditional special use factors, including public health and safety, effects on neighboring property, orderly development, roads, drainage and traffic congestion.

The County denied two solar applications after proceedings before its zoning board, zoning committee and county board. The stated concerns included drainage and runoff, proximity to residential development, airport glare and impacts on surrounding property.

The developers sought mandamus, arguing that the words “shall be approved” deprived the County of discretion. The Fourth District disagreed.

The court emphasized that the statute authorizes counties to establish “standards” while prohibiting only “requirements” more restrictive than those permitted by state law. It concluded that local standards may include broader, subjective considerations so long as they do not impose prohibited technical requirements.

The court also relied on the legislature’s decision to retain the special use process and require a public evidentiary hearing. Special use decisions traditionally involve judgment about whether a proposed use is compatible with a particular location. If technical compliance automatically required approval, the court observed, the hearing would be little more than a spectacle.

The Fourth District directly rejected the reasoning of Equity Solar, stating that “minimized discretion is still discretion.” Since some discretion remained, mandamus could not be used to compel approval, even if the County had exercised its judgment incorrectly.

What The Split Means For Townships

Townships generally do not issue county zoning approvals, but they should not wait until construction equipment appears on a township road before becoming involved.

A township or road district should obtain the proposed construction routes, anticipated vehicle weights, delivery schedules, access points, drainage plans and decommissioning materials while the county application is pending.

Section 5-12020 permits road use agreements that make a developer responsible for reasonable road improvements and repairs attributable to construction. Those agreements cannot require unrelated improvements or charges that are not specifically tied to the project.

That distinction should shape the township’s approach. A road district may document that a particular culvert, bridge, shoulder or pavement section cannot accommodate repeated heavy construction traffic without improvement. It should not use the project to fund a general road reconstruction program.

Drainage concerns should be handled the same way. The township should identify specific ditches, culverts, tiles and drainage patterns that may be affected and support its concerns with measurements, photographs, engineering information and testimony from personnel familiar with the site.

Building A Defensible Record

Until the Illinois Supreme Court or General Assembly resolves the conflict, local governments should prepare as though either interpretation could apply.

First, become involved early. Waiting until the final county board meeting leaves little time to develop competent evidence.

Second, distinguish evidence from opposition. A crowded hearing does not prove that a road is inadequate or that a drainage design will fail. Load ratings, traffic data, photographs, measurements and engineering reports create a much stronger record.

Third, connect each concern to lawful authority. A court applying Equity Solar will ask whether the requested condition is actually permitted. A court applying Tate Road Solar will still expect evidence showing how the application fails a valid local standard.

Fourth, make written findings. A bare “no” vote provides little assistance to defense counsel. The decision should identify the evidence relied upon, the applicable standard and how the application satisfies or fails that standard.

The Defense Perspective

The proper response to solar development is neither automatic approval nor reflexive opposition. It is disciplined governmental decision making.

Local governments should identify the authority they possess, impose only conditions they can legally support, document project specific impacts and create a record explaining their decisions. Township and road district officials should focus on roads, drainage, access and public safety.

Illinois has adopted statewide solar standards, but the appellate courts now disagree over the point at which local judgment ends and mandatory approval begins. Until that conflict is resolved, the best defense is a lawful ordinance, reliable evidence, carefully supported findings and a record that shows considerably more than which way the board voted.

Steve Judge is a municipal defense attorney and principal of Judge Law, LLC, representing Illinois townships and public entities in litigation, governance, and risk management.