The rate was fixed the day the job was advertised, not the day you work it: California prevailing wage

Your estimator pulls the rate sheet in March, prices four thousand hours of labor off it and wins the job. The crew that pours the last slab shows up fourteen months later, on a rate that has moved twice since. Whether that is a problem or a non event was settled before the bid was even submitted, by a date most contractors never write down.

On California public work the wage determination in force on the day the agency advertised the project governs the job for its whole life (Lab. Code s.1773.2). Not the current one. Not the one in force when you signed. The advertisement date one, frozen, all the way through the punch list.

That cuts both ways, and both ways are good for the contractor who knows about it. This page is which determination is yours, the increases that ride inside it, what actually counts toward the hourly obligation, the daily overtime trigger, and what underpaying costs when somebody adds it up.

Where the obligation starts

Prevailing wages apply to public works over $1,000 (Lab. Code s.1771). That is a low bar on purpose. It is not a threshold separating big jobs from small ones, it is a threshold separating public money from private money, so a four thousand dollar repair for a school district sits inside the same rules as an interchange.

The obligation is per worker, per hour, per classification. The Director of Industrial Relations issues determinations by craft, classification or type of work for each locality (Lab. Code s.1773), and the awarding body has to specify the applicable rates in the call for bids and post them at the job site (Lab. Code s.1773.2). Your job is to read the right one and price it into the bid before anybody swings a hammer.

Registration and certified payroll ride alongside all of it and neither is optional. DIR registration and certified payroll in California covers who has to be registered, the July 1 renewal, and the 10 days you get to produce records when somebody asks.

Which determination governs, and why the advertisement date is the one to write down

General wage determinations issue twice a year and take effect 10 days after issue. The one in force on the date the project was advertised for bid is the one that governs, and it governs for the life of the job.

Three consequences, all of them worth money.

• A determination issued after your advertisement date does not reach into your job. The rate you priced holds while the state's current rates move past it.
• A determination issued before your advertisement date but effective after it is not yours either. The effective date sits 10 days behind the issue date, and the comparison is against the advertisement date, so that ten day gap alone decides which sheet you are on.
• A readvertised job gets a new advertisement date. Rebid work is not automatically priced off the old sheet.

Put it on a calendar and it stops being abstract.

Now change one thing. If the agency had advertised on 2 March 2026 instead of 12 March, you would be one determination back and every labor line in the estimate would come off a different sheet. Ten days is the entire difference. That is why the advertisement date belongs on the first page of the job file next to the bid date, rather than buried in the invitation, and why the Caltrans and public works bidding guide starts at the bid documents.

Double asterisks are money you already owe

Here is the exception that eats margin on long jobs, and it is written into the determination itself rather than into the statute.

A determination carrying a double asterisk holds predetermined increases: rates that are already decided, already published and already scheduled to take effect on a date in the future. They are part of the determination that governs your job. Being frozen to the advertisement date does not freeze you out of those increases, it freezes you into them.

So the labor estimate is not one rate times total hours. It is:

1. The hours by craft that land before the increase date, at the current rate.
2. The hours by craft that land after it, at the increased rate.
3. The same split again for every further increase inside your schedule.

Take the job above, advertised 12 March 2026, with a predetermined increase on the carpenter line effective 30 June 2027 and 3,000 carpenter hours scheduled after that date. Every one dollar an hour of increase on that line is three thousand dollars off the job. If your estimate priced all 3,000 of those hours at the 2026 rate, you did not lose that money in the summer of 2027. You lost it in March 2026, before the bid was even opened.

This is the most knowable risk on any public job. The increase is published, the effective date is published, and your own schedule tells you how many hours fall on each side of it. Price it and it is a line item; ignore it and it is a surprise, and it is the identical number either way. Split the hours first, then run the loaded labor cost through the markup and margin calculator so the increase lands in the bid price instead of in your margin. What to charge as a California contractor covers building the rest of the rate up from cost.

What actually counts toward the obligation

A determination is not one number. It is a basic hourly rate plus employer payments, and what you owe is the total of the two.

The employer payments that count are the ones made for the worker's benefit under a bona fide plan: health and welfare, pension, vacation and holiday, apprenticeship or other approved training, and similar fringe contributions (Lab. Code s.1773.1). You can pay that portion into the plans, or as cash on the paycheck, or as a mixture of both. What you cannot do is land under the total.

What does not count is anything you were required to pay anyway. Payroll taxes and workers compensation premiums are the cost of employing anybody in California, on any job, public or private, so they do not credit against the prevailing wage package (Lab. Code s.1773.1). A contractor who puts those on the wrong side of the line underpays every single hour of the job by exactly that amount, and finds out in an audit rather than in a spreadsheet. Workers compensation for California contractors treats that premium as the separate cost it is.

Where the applicable determination provides for travel and subsistence, those are owed too (Lab. Code s.1773.8). That matters most on the jobs that pay best, which are usually the ones far enough out that nobody local wants them.

Classification is the other half of the total. It follows the work actually performed, not the title on your org chart and not the rate you would prefer to pay. A worker who performs two classifications in a day is owed each one for the hours worked in it, and the certified payroll shows the split. Classification errors, rather than deliberate underpayment, are where most of the exposure in the next section comes from.

Overtime is a day, not just a week

Public work in California pays overtime after 8 hours in a day or 40 in a week (Lab. Code s.1811). Overtime pays not less than 1.5 times the basic hourly rate (Lab. Code s.1815), and the employer payments still attach to every hour worked, straight time and overtime alike.

The daily trigger is what catches contractors who run compressed schedules on private jobs. Do the arithmetic before you promise one.

A crew of 6 works four 10 hour days. That is 40 hours in the week, which looks clean, but under Lab. Code s.1811 each of those days carries 8 hours at straight time and 2 hours at the overtime rate. That is 8 overtime hours per worker per week, 48 across the crew, and across a 12 week stretch, 576 overtime hours nobody priced.

Schedule provisions live inside the determination for the craft, and they differ by craft and by locality, so the answer for your carpenters is not automatically the answer for your operators. Get that answer while the schedule is still a draft and it costs you an afternoon of reading. Get it after the schedule is published and it costs 576 hours.

What underpaying costs

Underpayment is not something you fix later by paying the difference.

• The shortfall between what was paid and the determination is owed to the worker, and a penalty runs for each calendar day, or portion of a day, that each worker was paid less than the determination requires (Lab. Code s.1775).
• Overtime hours worked without the overtime rate carry a separate per day, per worker penalty of their own (Lab. Code s.1813).
• The awarding body withholds it from progress payments, and it withholds at the top of the chain regardless of which tier got it wrong (Lab. Code s.1775).
• A prime carries exposure for a subcontractor's underpayment, which is why primes police subcontractor payroll harder than agencies ever do (Lab. Code s.1775).
• Willful violations lead to debarment from bidding public work for a fixed period (Lab. Code s.1777.1). That does not end a job, it ends a market.

Failure to produce certified payroll records within the 10 days after a written request carries a penalty of its own as well (Lab. Code s.1776), separate from anything to do with the wages themselves.

Read the list together and the shape is obvious. The penalties are per worker and per day, so the cost scales with crew size and with how long the error ran before anybody noticed. One laborer in the wrong classification, caught in week two, is a correction. The same mistake across eight workers for nine months is a different order of number, out of exactly the same error. Which is the argument for reading your own certified payroll every period instead of signing it: the classification column is the early warning system, and it is already in your hands.

Extra work is prevailing wage work

One more place this gets missed. Change order work on a public job is public work. The classification rules, the overtime rules and the certified payroll all apply to it, and the rate is still the one fixed on the advertisement date, increases included. When you price an extra with a labor number, that number carries the determination with it, so a change order priced off your private-work labor rate is short before it is even submitted. Change orders and getting paid for extras in California covers getting the authorization in writing before the crew is standing there waiting.

Put the advertisement date on the first page

Everything above runs off a single input you can get for free on the day you decide to bid: the date the project was advertised. From that date you get the determination. From the determination you get the rates by craft and locality. From the double asterisk lines you get every increase you will pay before the job closes out. After that it is arithmetic, and arithmetic is knowable in advance, which is the whole difference between a public job that makes money and one that just keeps the crew busy.

On AEC Stack there is no monthly subscription. The platform fee is 2.5 percent of each invoice processed through the platform, so the labor rates, the increase dates and the payroll that proves them sit in the same job record as the billing they produce.

Take the public job you are pricing right now, find the advertisement date in the invitation, and split your labor hours around every predetermined increase inside your schedule. Open a working demo business file and get the crafts, the hours and the increase dates against the job before the bid goes in.