Illinois Mechanics Liens: What Contractors Must Include in the 90-Day Notice to Protect Their Rights

Poor documentation and procedural errors rank among the leading causes of construction disputes—costing businesses $52.6 million on average in global dispute value. One of the most common pitfalls is failing to meet the requirements for the 90‑day mechanics lien notice in Illinois. If you’re a contractor, subcontractor, or supplier in Chicagoland, a single oversight—like omitting a detail or missing a mailing deadline—can turn a valid claim into an uncollectable loss. 

The stakes are high, and the margin for error is razor-thin. Grzymala Law Offices understands how every nuance of your paperwork affects your bottom line. If you want to make sure your 90‑day notice is airtight, reach out now.

What Contractors Must Include in the 90-Day Notice

The Illinois Mechanics Lien Act (770 ILCS 60/24) sets out clear and strict rules for every contractor, subcontractor, and supplier who is not directly contracted with the property owner. Missing or misplacing even one required element in your 90-day notice can wipe out your mechanics lien rights. Here’s what must be included to ensure full legal protection:

Claimant’s Name and Address

Every 90-day notice must clearly state the full legal name and current address of the subcontractor or supplier who is asserting the lien claim. The law requires an unmistakable identification of who is seeking payment. Errors in the business name, use of an outdated address, or omitting key information can cause confusion for the property owner and may give them grounds to challenge or disregard your notice altogether. For a mechanics lien Illinois claim to hold up in court, your identity must be precise and traceable, linking the work performed directly to your business.

Description of Labor or Materials Provided

A successful Illinois mechanics lien lawyer knows that being specific about the labor performed or materials supplied can make or break your claim. The notice should go beyond generic terms like “work performed” or “materials furnished.” Instead, it must describe in detail what services were rendered or what products were delivered. 

For example, specify “installation of custom cabinetry in kitchen remodel” or “delivery of 1,200 square feet of hardwood flooring for first-floor renovation.” This clarity allows the property owner and any lender to verify that the lien relates directly to improvements on the property, and it provides essential evidence if the claim is disputed down the line.

Exact Property Identification

Illinois courts are unforgiving when it comes to vague property descriptions. Your 90-day notice should list the exact street address of the improved property and, if available, the legal property description as it appears on public records. Failing to properly identify the property is one of the leading causes for rejected lien claims in Illinois. This requirement is intended to prevent confusion about which parcel is encumbered by the mechanics lien, and to ensure all parties—owners, lenders, and future buyers—know precisely which property is involved.

Unpaid Amount Owed

You must include the specific dollar amount that remains unpaid as of the date the 90-day notice is served. The amount should align with your supporting documentation, such as invoices, contracts, or delivery slips. This clarity is critical: overstating the amount can lead to accusations of fraud, while understating it means forfeiting potential compensation. Every claim should be supported by a paper trail, making it easy to prove the sum owed in a dispute.

Date of Last Work or Delivery

Illinois mechanics lien rights depend heavily on timing. Your 90-day period for sending notice starts from the last date you provided labor or materials to the project. Entering the wrong date—whether accidental or intentional—can result in your notice being considered late, voiding your claim. Carefully track your final day on site or last delivery, and double-check all project logs. The most reliable Chicago mechanics lien lawyer will ensure this date is exact, as any error can mean missing the statutory deadline.

Owner’s Name and Address

The 90-day notice must be delivered to the legal owner of the property, and to any lender with an interest in the property. It’s crucial to verify the owner’s identity and mailing address using public records, your original contract, or a title search. Delivering notice to the wrong party is as fatal as not serving notice at all. If a lender is involved, their correct contact information must be included to protect your rights against the lender’s interest.

Signature

No mechanics lien notice is valid in Illinois without a proper signature. The notice must be signed and notarized by you, your authorized company officer, or your Illinois mechanics lien attorney. Unsigned notices simply do not meet statutory requirements and are quickly dismissed by courts. A signed notice is proof that the information provided is correct and submitted in good faith.

Service of the notice is just as important as its content. Illinois law now permits three tracked delivery methods for the 90-day notice: (1) personal service; (2) USPS certified mail; or (3) any nationally recognized carrier with tracking, such as FedEx, UPS, or DHL (HB 4660, eff. Jan 1 2025). Choose the method that provides the clearest proof of delivery, and always retain the carrier’s tracking record. 

Complete Your Illinois 90-Day Notice Correctly with Grzymala Law Offices

When your right to payment is on the line, every word and date in your 90-day notice matters. The experienced team at Grzymala Law Offices helps contractors, subcontractors, and suppliers across Illinois meet every legal requirement and deadline for mechanics lien, maximizing your leverage and protecting your bottom line. If you need to prepare, review, or serve a 90-day notice, or want a full mechanics lien strategy that stands up in court, contact us today—and trust Grzymala Law Offices to defend every dollar you’ve earned.