Illinois Performance Bond Guide: 30 ILCS 550 Explained
Public property in Illinois can't be liened. When a prime contractor doesn't pay a sub or supplier on a city, county, school district, or state job, there is no mechanics lien to file — the payment bond required by 30 ILCS 550 is the remedy. This guide decodes the statute clause by clause for both sides: the GC who has to post the bond, and the sub or supplier who has to claim on it.
If You're the GC
You post the bond before the contract is awarded. Miss the threshold call and the public body can reject your bid.
If You're a Sub or Supplier
You have 180 days from your last day of work to file a notice of claim — or you lose your only remedy.
New to bonding? Start with what a surety bond is, or jump to our performance bond calculator.
Official Illinois Requirements
"Officials, boards, commissions, or agents of the State, or of any political subdivision thereof, in making contracts for public work in an amount in excess of $150,000, shall require every contractor to furnish, before commencing the work, a bond with good and sufficient sureties for completion of the contract and payment for material and labor."Illinois Public Construction Bond Act • 30 ILCS 550/1
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What 30 ILCS 550/1 Actually Requires, Clause by Clause
The statute is short, but four clauses do all the work. Here's what each one means in practice.
"Officials, boards, commissions, or agents of the State, or of any political subdivision"
This covers every public body — state agencies, the Capital Development Board, IDOT, the Illinois Tollway, counties, municipalities, park districts, and school districts. There is no carve-out for "small" local governments; a village of 4,000 people is bound by the same statute as the State itself, just at a different dollar threshold for IDOT/Tollway work.
"in an amount in excess of $150,000"
This is the dollar line that turns the bond from optional to mandatory for the public body. It was $50,000 before January 1, 2024, jumped to $150,000 under Public Act 103-570, and is scheduled to revert to $50,000 on January 1, 2029. IDOT and Illinois Tollway contracts use a separate $500,000 line that the 2029 sunset does not touch.
"a bond with good and sufficient sureties"
The surety itself has to be licensed by the Illinois Department of Insurance and carry a financial strength rating of at least A- from AM Best, Moody's, S&P, or an equivalent rating agency. A bond from an unrated or low-rated carrier can be rejected by the public body outright — always confirm your surety's rating before you bid, not after you win.
"completion of the contract, and payment for material and labor"
Two obligations, usually two bond forms: a performance bond protecting the public body if you default on the work, and a payment bond protecting every sub-contractor and supplier who furnished labor or material — "either as an individual or as a sub-contractor," per 30 ILCS 550/2. Both are typically written at 100% of the contract price.
Illinois General Bonding Threshold: A Temporary Increase, Not a Permanent Rule
Bond Requirement Increase
Previous Requirement
$50,000
New Requirement
$150,000
Bidding a multi-year contract that spans the sunset date? The threshold that applies is set by your contract award date — confirm it with your producer before you rely on either number.
Which Threshold Applies to Your Obligee
"Public body" isn't one entity in Illinois — it's four very different obligees with two different dollar lines under the same statute.
State Agencies & Capital Development Board
CDB manages vertical state construction — university buildings, state office facilities, corrections projects. It's a state agency, so it sits at the general $150,000 threshold like any other agency, not the higher IDOT/Tollway line.
IDOT & Illinois Tollway
Road and bridge work for the Illinois Department of Transportation and the Illinois State Toll Highway Authority is carved out at a $500,000 threshold — more than triple the general rule, and not scheduled to change in 2029.
City of Chicago & Home-Rule Municipalities
Chicago is a political subdivision under 30 ILCS 550, subject to the same $150,000 general threshold. As a political subdivision (not the State itself), it also qualifies for the letter-of-credit alternative on non-state-funded contracts under $100,000.
School Districts & Community Colleges
Also political subdivisions at the $150,000 threshold. Districts can still require a bond on smaller contracts through board resolution — check bid specs, since roofing and HVAC jobs often fall under $150K.
30 ILCS 550/1 Bonding Threshold by Obligee Type
Same statute, two different dollar lines — confirm which one governs your project
| Obligee | Statutory Threshold | Reverts to $50K in 2029? | Letter of Credit Alternative |
|---|---|---|---|
| State agency / Capital Development Board | $150,000 | Yes | No — State contracts excluded |
| IDOT / Illinois Tollway | $500,000 | No | No |
| City of Chicago (political subdivision) | $150,000 | Yes | Yes, under $100K, non-state funds |
| County / municipality | $150,000 | Yes | Yes, under $100K, non-state funds |
| School district / community college | $150,000 | Yes | Yes, under $100K, non-state funds |
Letter of credit alternative applies only to political subdivisions (not the State) on contracts under $100,000 funded with non-state money.
Source: 30 ILCS 550/1, Public Construction Bond Act
The Claim Clock: 180 Days to Notice, One Year to Sue
Under 30 ILCS 550/2, subs and suppliers who aren't paid have exactly one remedy — and two hard deadlines to preserve it.
Day 0: Last Furnished Labor or Material
The clock starts on the date you last worked or delivered materials on the project — not the date you invoiced, and not the date payment was due.
Day 180: Verified Notice of Claim Due
You must serve a verified notice of claim on the contractor and the public body within 180 days of day 0. This is not a formality — miss it and your bond claim is permanently barred, regardless of how much you're owed.
Day 365: Deadline to File Suit
Suit on the bond must be filed within one year of day 0 — not one year from your notice of claim. Waiting to see if a dispute resolves informally is the most common way contractors run out this clock.
Compare this to private work: on a privately owned project, you'd have four months to record a mechanics lien under 770 ILCS 60/7. Public work gives you longer — 180 days — but it's a bond claim, not a lien, and the deadline is just as absolute.
What an Illinois Performance Bond Costs
Performance and payment bonds price together as a package, based on credit and financial strength — not a flat percentage.
Illinois P&P Bond Premium by Credit Tier
Based on a $500,000 contract bond amount
- Excellent (720+)Rate: 0.5%–1%$2,500–$5,000
- Good (680–719)Rate: 1%–1.5%$5,000–$7,500
- Fair (620–679)Rate: 1.5%–2.5%$7,500–$12,500
- Challenged (below 620)Rate: 2.5%–4%$12,500–$20,000
Illustrative for a $500,000 contract. Actual quotes depend on financial statements and work-in-progress, not credit alone — credit matters more below $500K; above it, sureties weigh CPA-reviewed financials more heavily.
Run your own numbers with the performance bond calculator, or read the full surety bond cost guide.
Working a Federal Job in Illinois Instead? Different Statute, Similar Idea
30 ILCS 550 only governs Illinois state and local public work. If your project is federally funded — a VA hospital renovation, a federal courthouse, GSA work — the controlling law is the Miller Act, 40 U.S.C. §§ 3131–3134. The statutory trigger there is contracts over $100,000, though the Federal Acquisition Regulation applies the requirement in practice above $150,000 — and both the performance and payment bonds are set at 100% of the contract price, same structure as Illinois's own bond, just a different rulebook and a different claims process.
Illinois Performance Bond FAQs
Questions from GCs posting the bond and subs claiming on it
Why can’t I just file a mechanics lien if an Illinois public contractor doesn’t pay me?
What is the current Illinois performance bond threshold, and why does it say "temporary"?
Does a public body have to require a bond below the $150,000 threshold?
How long do I have to file a claim on an Illinois public construction bond?
Can a public body still hold 10% retainage on my Illinois public contract?
Is there a way to avoid posting a bond on a smaller Illinois public contract?
Does the Capital Development Board require the same bond as a city or school district?
What does an Illinois performance bond cost compared to a payment bond?
Bidding a CDB, IDOT, or Chicago Contract?
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