How to Bid Illinois Prevailing Wage Jobs Without Losing Money
By the Illinois Construction Estimators estimating team. Published October 24, 2026. 8 min read.
To bid an Illinois prevailing wage job without losing money, price every labor hour at the Illinois Department of Labor rate for that county and trade, add the full fringe benefit rate, and confirm you’re using the current year’s schedule. Most prevailing wage losses come from skipping one of those three steps.
What the Prevailing Wage Act covers
The Illinois Prevailing Wage Act (820 ILCS 130) applies to public works: construction, alteration, repair and demolition paid for by a public body. That includes IDOT road and bridge work, county highway departments, municipalities, park districts, school districts and many projects financed with public bonds.
On covered jobs, every laborer, mechanic and worker must receive at least the general prevailing rate of hourly wages for similar work in the county where the job is built. Under the Act, that rate means the hourly cash wage plus fringe benefits, such as health and welfare, pension and approved apprenticeship training. If your estimate prices only the base wage, it is underpriced from the first line.
The Act also covers work done for a public body under a contract with someone else. If you are a subcontractor to a general contractor on a school addition, you pay prevailing wage just as the GC does.
State rates vs. Davis-Bacon rates
Jobs paid for with federal money may fall under the federal Davis-Bacon and Related Acts instead of, or in addition to, the Illinois Act. Federal rates come from the U.S. Department of Labor’s wage determinations, published on SAM.gov.
| Illinois Prevailing Wage Act | Davis-Bacon Act | |
|---|---|---|
| Applies to | Public works paid for by Illinois public bodies | Federally funded or assisted construction |
| Rates set by | Illinois Department of Labor, by county | U.S. Department of Labor, by area and construction type |
| Where to find rates | IDOL website | SAM.gov wage determinations |
| Updated | Annually, after IDOL’s June survey | As wage determinations are revised |
When both apply, the bid documents will say so. Price each classification at the higher of the two rates so you never fall below either.
How to read a county rate schedule
IDOL publishes prevailing wage rates for every Illinois county. The 2026 rates took effect July 15, 2026, following the department’s annual statewide survey in June.
Each county schedule lists trade classifications (carpenter, laborer, electrician, operating engineer and so on), with columns for the base wage, foreman rate, overtime rules, and fringe amounts such as health and welfare, pension, vacation and training. A few points trip estimators up:
- Some trades have different rates for building, highway and heavy work in the same county.
- Operating engineers often have several classes based on the equipment run.
- Overtime and holiday rules vary by trade; read the notes column, not just the rate.
- Cook County, the collar counties and downstate counties can differ sharply for the same trade.
Building the labor cost into your estimate
A reliable prevailing wage labor rate is built in layers. Start with the county schedule, then add the costs you carry as an employer.
| Layer | Where it comes from |
|---|---|
| Base hourly wage | County schedule, by classification |
| Fringe benefits | County schedule: health, pension, vacation, training |
| Payroll taxes | FICA, federal and Illinois unemployment |
| Workers’ compensation | Your insurance rate for each trade code |
| Liability insurance | Your policy, often a percentage of payroll |
Multiply the loaded hourly rate by the labor hours from your takeoff. That is why a good quantity takeoff matters: hours come from quantities, and quantities come from the drawings.
Five mistakes that lose money
| Mistake | How to avoid it |
|---|---|
| Using last year’s rates | Check the schedule date against the bid opening. A bid after July 15, 2026 needs the 2026 rates. |
| Using your shop’s county | Price to the county where the job is built. |
| Leaving out fringe | Add the full fringe amount to every hour. |
| Wrong classification | Match each task to the trade that performs it under the schedule. |
| Overtime at straight time | Apply each trade’s overtime and holiday rules if the schedule needs extended hours. |
Compliance costs to carry in your bid
Prevailing wage work carries office costs that private work doesn’t. Contractors must post the rates at the job site and file certified payroll through IDOL’s online portal. According to IDOL, a contractor found to have violated the Act twice in five years may be barred from public works for four years.
Budget time for certified payroll preparation, apprenticeship paperwork if the bid requires it, and project closeout documents. On small public jobs, these hours can be a meaningful share of overhead.
Flow the requirements down. Your subcontract agreements should require every sub and lower-tier sub to pay prevailing wage, post the rates and submit certified payroll on time. A late or missing payroll from one sub can hold up payment on the whole job.
A pre-bid checklist for public jobs
Run through this list before you submit any Illinois public bid:
- Confirm whether the Illinois Act, Davis-Bacon, or both apply, from the bid documents.
- Download the current IDOL schedule for the project’s county and save a dated copy with your estimate.
- Map every task in your takeoff to a trade classification on that schedule.
- Load each labor rate with fringe, payroll taxes, workers’ compensation and liability insurance.
- Apply overtime rules wherever the schedule or phasing needs extended hours.
- Ask every subcontractor to confirm in writing that their quote includes prevailing wage.
- Add office time for certified payroll and closeout paperwork to your overhead.
The sixth step matters more than most contractors expect. If a subcontractor’s quote was built on private-work rates, the gap becomes your problem after award.
Where to find the rates for a specific bid
Start with the bid documents. Under the Act, bid specifications for public works must list the prevailing rates that apply, and the public body awarding the contract is responsible for including them. If the specs reference a rate schedule by date, compare it with the current IDOL schedule for the county.
If IDOL publishes a revised rate after the contract is awarded, the public body must notify the contractor, and the new rate applies from that point. Keep a dated copy of the schedule you priced with, so you can show what your bid was based on if rates change mid-project.
Frequently asked questions
Generally no. The Act covers public works paid for by public bodies. A private project can still require it by contract, so read the bid documents.
IDOL surveys rates in June and publishes new county schedules each summer. The 2026 rates took effect July 15, 2026.
Yes. The prevailing rate is the hourly cash wage plus fringe benefits, so price both on every hour.
Yes. We price public-work estimates to the current IDOL rates for the county where your project is located.
Have a public bid coming up? Our Illinois construction estimating services include prevailing wage pricing for every county, and our Springfield and Peoria teams price public work every week.
Related: Rebuild Illinois: Where the Road and Bridge Bids Are in 2026. Public bidders near Chicago, Joliet and Champaign-Urbana can find local county details on their city pages.