DeKalb County Property Tax, DBA Registration and Food Permit Guide

DeKalb County lies directly west of Kane County and is home to the cities of DeKalb and Sycamore as well as farmland and smaller towns. Its offices cluster in Sycamore, and its numbers differ from the suburban counties nearby: lower sales tax rates, a different installment schedule and a published food permit fee list. This guide explains DeKalb County property tax, the 2026 appeal deadline, how to register an assumed business name and what a restaurant or caterer should expect to pay the Health Department.

Which DeKalb County offices matter to owners?

Most of these offices share the Administration Building at 110 E. Sycamore Street in Sycamore, open 8:30 am to 4:30 pm.

What are the DeKalb County property tax dates?

Illinois property taxes are billed one year behind, in two installments on a single bill. The Treasurer's page for 2025 taxes payable in 2026 gives:

You can pay online through the county's real estate tax portal, in person on the fourth floor of the Administration Building, by mail with the installment stub and your parcel number written on the check, or at participating banks for real estate taxes only, with the whole bill. Card payments online carry a processor fee. Mail early because postmarks may be delayed, and postmarks are not accepted after certified delinquent notices are mailed.

If you buy property mid-year, taxes belong to the parcel, so use the closing statement to see how the seller's share was credited. Our Illinois compliance calendar tracks local deadlines alongside state ones.

How do you appeal a DeKalb County assessment?

The Assessment Office advises talking to the township assessor first because many issues are resolved without an appeal. If not:

1. Confirm your grounds: market value too high, inequity compared with similar properties, an incorrect physical description, or a question of law.
2. Obtain the 2026 residential or commercial appeal packet from the Assessment Office (fourth floor of the Administration Building) or the county site.
3. Read the Board of Review rules.
4. Submit the appeal and all evidence so that it is received or postmarked by the deadline.
5. For 2026, the notice for the listed townships, including DeKalb, Sycamore and Cortland, was published September 10, 2026 and the filing deadline was October 13, 2026. A 10-day extension moved it to October 27.
6. If the Board's decision still looks wrong, the county's PTAB page explains the state appeal.

Exemptions and farmland assessments are separate programs; the Assessment Office chairs the county's Farmland Assessment Review Committee, which matters because farmland is valued on agricultural productivity rather than market price. If you hold farmland and also live in Kane or Kendall County, compare the programs in the Kane and Kendall guides.

How do you register an assumed business name in DeKalb County?

Sole proprietors and general partnerships register with the County Clerk of the county where they operate. Corporations, LLCs, limited partnerships and LLPs register with the Illinois Secretary of State. Professional service corporations whose names do not include a shareholder's name register with the clerk in the county of their principal place of business.

1. Complete the Assumed Name Registration form and sign it before a notary or a deputy clerk.
2. File it with the $5.00 fee.
3. Publish the notice the Clerk prepares once a week for three consecutive weeks in a DeKalb County newspaper, starting within 15 days of filing.
4. File proof of publication within 50 days.
5. Receive the Certificate of Business Ownership by mail.

Adding or removing an owner or dissolving a registration uses the Supplementary Registration form, with a $1.50 fee and publication if 25% or more of ownership moves. A change of address or owner name also costs $1.50 with no publication. The clerk offers a confidential address request form. For the larger picture, see the assumed name guide.

What do DeKalb County food permits cost?

The Health Department licenses and inspects more than 500 restaurants and retail food establishments and also inspects temporary vendors. Plan review takes about a week, and drawings must be to scale but need not be architectural plans.

Permits are not transferable between owners or locations. A late fee of 50% of the permit cost applies to restaurants, and card payments add a 2.25% fee. If your premises is in a city or village, check that town's licenses as well.

What sales tax rates apply?

The Illinois Department of Revenue's county row for DeKalb County is the 6.25% state rate, unchanged by the August 1, 2026 regional transit increase that covers only Cook, DuPage, Kane, Lake, McHenry and Will. The cities add their own: DeKalb and Sycamore are at 8.00%, and the DeKalb County part of Sandwich is 7.25%. Qualifying groceries are 1.00% in DeKalb, Sycamore and Sandwich. Read our Illinois sales and use tax guide before you register.

Where can DeKalb County businesses get help?

The DeKalb County Economic Development Corporation lists Kishwaukee College's Center for Business Development and Continuing Education, the Illinois Small Business Development Center at Waubonsee Community College and the DeKalb County chapter of SCORE. It also supports an Enterprise Zone advisory board and promotes the county's manufacturing, education, healthcare, logistics and agriculture base. See the small business resources guide for financing paths.

A quick example

Noah plans a small bakery in Sycamore with a catering side line. He files an assumed name for $5.00 with the County Clerk, publishes it for three weeks, applies for a Class B permit with catering at $665, and pays a $540 plan review. If instead he forms an LLC, he skips the county name filing but still pays the Health Department fees.

Mistakes to avoid

• Missing the early October appeal deadline because no notice arrived by mail.
• Waiting until the sale list is published to pay a delinquent bill.
• Assuming a Kane or Kendall County fee applies to DeKalb permits.
• Forgetting that the County Clerk and the Secretary of State handle different business types.

How we can help

Our firm is based in the Aurora and Fox Valley area and supports DeKalb County clients with U.S. returns, entity choices, payroll, sales tax and bookkeeping. Where family or accounts are in India or Canada, we coordinate with your Canadian CPA or Indian Chartered Accountant so the filings agree. Start with business formation and registrations or business tax returns and planning.

Frequently asked questions

General information only. It is not tax, legal, accounting or immigration advice for your situation, and rules change; confirm the current rules with the official source or a licensed professional in the relevant country.