Public works: DIR registration before you bid, prevailing wage over $1,000, and certified payroll every week
In one paragraph
A school lighting retrofit, a city hall panel, an EV charger in a public parking lot: if public money pays for any part of it, it is public work. You cannot bid on it or perform it unless you are registered with the Department of Industrial Relations ($400 a year), you must pay the state prevailing wage on any project over $1,000, and you must keep certified payroll records under penalty of perjury. The small-project exception ($25,000 for construction, $15,000 for maintenance) lifts the registration requirement, not the prevailing wage. Here is the whole frame before you price your first public job at private rates.
The rule
Public works is construction, alteration, demolition, installation or repair done under contract and paid in whole or in part from public funds (Labor Code 1720(a)(1)). On any public works project over $1,000 all workers must be paid not less than the general prevailing rate (Labor Code 1771). A contractor or subcontractor is not qualified to bid on, be listed in a bid for, or perform public work unless registered with the DIR (Labor Code 1725.5, 1771.1(a)), except on projects of $25,000 or less for construction, alteration, demolition, installation or repair, or $15,000 or less for maintenance (1771.1(n)). Registration costs $400 per fiscal year (DIR). Certified payroll records are kept and made available under Labor Code 1776.
Why it matters
A new contractor who prices a school job at residential rates and pays helpers residential wages faces back wages, penalties and a DIR debarment before the job is done, and the awarding body cannot even accept the bid without proof of registration. Public work is a steady, well-paying channel once the compliance is built; it is a trap when it is not.