A Kane County owner challenges a 2026 assessment by filing the county's paper complaint form with the Kane County Board of Review within the township-specific publication window. The electronic evidence portal is not an initial complaint portal. The county expressly requires complaints to arrive by United States Mail, private courier, or in person at the Geneva Board office, while fax and email are rejected. FairPath can help an owner manually organize the current form, parcel details, owner-selected sales or EAV comparisons, condition records, and delivery proof. It does not mail or deliver the complaint, act as a representative, or claim an automated Kane County filing product.
Assessment context: Kane County township assessors establish and maintain local assessments, and the Board of Review is the formal county authority that evaluates complaints for overvaluation, inequity, physical-data discrepancy, or preferential assessment. The county says fair cash value for 2026 is measured as of January 1, 2026 and ordinarily uses sales from 2023 through 2025. Assessed value is generally one-third of fair cash value before equalization. A percentage increase, tax rate, or final bill amount is not itself a valid assessment-complaint basis. Confirm the property's PIN, township, current EAV, property characteristics, and owner or taxpayer standing before selecting evidence, especially where a property has multiple or contiguous parcels.
Filing process: First, check the county Filing Deadlines page because published and pending township dates appear side by side. Download the current Residential/Farm or other applicable complaint form, complete the required identification, oath, reason, comparable section, hearing choice, and taxpayer opinion, and include authorization where required. File the paper original with the Clerk of the Board at 719 Batavia Avenue, Building C, Geneva, Illinois 60134 by mail, courier, or personal delivery. A United States Postal Service complaint is generally filed on its postmark date, while a private delivery service uses its tracking-label sent date under the rules. The evidence portal cannot open or preserve a complaint. Save a complete copy and dated postmark, tracking receipt, or stamped delivery proof.
Evidence to review: Kane's 2026 residential form calls for at least three comparables. For overvaluation, use sale comparables from 2023, 2024, or 2025; for equity, use 2026 EAV comparables. Prefer nearby properties or the same subdivision with similar land area, style, construction, age, baths, living area, basement finish, bedrooms, garage, quality, and condition. A physical-data complaint should include the subject property record card, identify the incorrect field, and provide competent proof such as a survey, photograph, or construction document. Evidence may accompany the paper complaint. After the township filing period ends, an already-filed complainant may use the electronic evidence portal for no more than 14 calendar days after the final deadline. That portal cannot cure a missing initial complaint.
Current deadline guidance: Township-specific 2026 deadline; published dates are live while remaining townships show TBD. Kane County requires a fully completed Board of Review complaint no later than 30 calendar days after publication of the current assessment list for the property's township. As reviewed July 15, 2026, the county listed Dundee's July 9 deadline as passed, Saint Charles due July 20, and Blackberry due July 27; all other township deadlines were still marked TBD. These dates change as rolls publish. Verify the property's township and the official Filing Deadlines page immediately before mailing, courier delivery, or in-person filing. Township-assessor discussions do not extend the deadline.
Kane County's deadline page is a live mixed-status calendar. Dundee's 2026 deadline had passed by July 15, Saint Charles was due July 20, Blackberry was due July 27, and Aurora, Batavia, Elgin, Geneva, and other townships still showed TBD. A countywide summary cannot replace the township row applicable to the parcel.
Kane separates complaint filing from electronic evidence submission. The initial complaint is paper-only through mail, courier, or in-person delivery. The evidence portal becomes available only after the township's 30-day complaint window closes, only for a complaint already filed, and closes 14 days after the final filing deadline.
The 2026 residential form distinguishes sales evidence from assessment-equity evidence by year. Overvaluation complaints use 2023 through 2025 sales, while equity complaints use 2026 EAV data. Mixing those measures without explaining the legal basis can make the comparison difficult to evaluate.
Incomplete complaint forms may be returned and are accepted on resubmission only if the filing deadline is still met. Review the PIN, signature, oath, reason, requested assessment, contiguous parcel information, and any authorization before dispatch. A mailing receipt does not repair a blank or unsigned form.
Official filing authority: Kane County Board of Review. https://assessments.kanecountyil.gov/Pages/Assessment-Complaints.aspx
Source: Kane County Assessment Office, 2026 Township Filing Deadlines, https://assessments.kanecountyil.gov/Pages/Deadline.aspx. Reviewed 2026-07-15.
Source: Kane County Board of Review, Assessment Complaints, https://assessments.kanecountyil.gov/Pages/Assessment-Complaints.aspx. Reviewed 2026-07-15.
Source: Kane County Board of Review, 2026 Rules and Procedures, https://assessments.kanecountyil.gov/Documents/Rules.pdf. Reviewed 2026-07-15.
Source: Kane County Board of Review, Electronic Evidence Submission, https://assessments.kanecountyil.gov/Pages/Evidence.aspx. Reviewed 2026-07-15.
Source: Kane County Board of Review, 2026 Residential and Farm Assessment Complaint, https://assessments.kanecountyil.gov/Documents/Complaint%20Forms/ResidentialFarm.pdf. Reviewed 2026-07-15.