A — General Engineering

A California Class A license is the General Engineering Contractor license: it authorizes you to bid and build fixed works that call for specialized engineering knowledge — earthmoving, grading, roads, pipelines, dams, and similar heavy civil infrastructure — rather than the buildings a Class B contractor constructs. To get one, you pass CSLB’s Class A trade exam and the Law & Business exam, prove four years of qualifying journey-level experience, and post a contractor bond.

What a Class A Contractor Actually Builds

Under California Business & Professions Code Section 7056, a general engineering contractor’s principal business is fixed works requiring specialized engineering knowledge and skill — things like irrigation, drainage, water supply, flood control, dams and hydroelectric projects, railroads, highways and streets, tunnels, airports, harbors and docks, sewers and sewage disposal systems, pipelines, and refineries or powerhouses, plus the earthmoving and grading that goes with them. In practice, that scope shows up on jobs such as:

• Mass grading and pad preparation for a new subdivision or commercial site, including cut-and-fill balancing and soil compaction to engineered specs.
• Subdivision infrastructure — installing the storm drain trunk lines, sewer mains, and water supply piping that a developer needs before vertical construction can start.
• Roadway and highway base work, including street and parking-lot subgrade, aggregate base, and paving structure (often bid alongside a Caltrans or municipal contract).
• Small dams, levees, or flood-control channels for a water district or county flood-control agency.
• Bridge, overpass, or culvert substructure work, including shoring, excavation support, and foundation placement for the structure.
• Pipeline and utility trenching for petroleum, gas, or water transmission lines that cross multiple parcels or rights-of-way.

Class A does not, by itself, authorize landscape installation (that’s C-27 Landscaping) or general building construction (that’s Class B) — see the comparison section below for where the lines actually fall.

Class A Trade Exam: What CSLB Actually Tests

Every applicant sits two separate, closed-book, multiple-choice exams: the Law & Business exam and the classification trade exam. Each is scheduled as its own PSI test-center appointment with a 3.5-hour time limit (confirmed on CSLB’s Examination FAQ). CSLB does not publish an exact question count or numeric passing score for the Class A trade exam specifically — if you see a site quote a precise number like “150 questions” or “73% to pass” for this classification, treat it as an estimate, not an official figure, unless it links back to CSLB.

What CSLB does publish, in its official General Engineering (A) License Examination Study Guide (effective for exams scheduled on or after February 1, 2025), is the exam’s content breakdown across eight sections:

1. Planning and Estimating — 15% (reviewing plans/specs, code compliance, evaluating job sites, coordinating with other trades, estimating materials/equipment/labor)
2. Structural Principles — 6% (constructing structures, seismic requirements, basic engineering)
3. Earthwork and Surveying — 15% (surveying and preparing job sites, assessing soil conditions, compaction and expansion)
4. Subsurface, Surface, and Elevated Piping Work — 21% (shoring/sloping excavations, erosion prevention, tunneling/drilling/boring, installing pipelines, connecting and testing systems, dry utilities)
5. Foundation and Concrete Construction — 11% (forms and falsework, placing/finishing concrete, pilings and foundations)
6. Buildings, Structures, and Related Work — 9% (mechanical, plumbing, and electrical installation; demolition, disposal, recycling)
7. Roadwork and Paving — 5% (base construction for highways, roads, and parking lots)
8. Safety — 18% (personnel/job-site safety, PPE, hazardous material safety)

Notice that Piping Work (21%) and Safety (18%) together make up more than a third of the exam — that’s where most Class A candidates should weight their study time. CSLB provides a calculator for math-heavy questions, and there is no penalty for guessing.

Class A License Requirements

Experience: four years of verifiable journey-level experience in general engineering work within the 10 years before you apply, documented by a certifier who can vouch for your work firsthand. Up to three of those four years can come from technical training, an approved apprenticeship, or education (for example, up to 1.5 years of credit for an associate degree, or more for a related four-year engineering or construction-management degree) — but at least one full year must be hands-on practical experience; you cannot substitute the entire requirement.

Application steps: submit CSLB’s Application for Original Contractor License with the current $450 non-refundable application fee, complete Live Scan fingerprinting for DOJ/FBI background clearance, wait for CSLB to review and issue a Notice to Schedule, then sit both exams at a PSI test center (PSI charges its own per-exam testing fee, separate from and in addition to the CSLB application fee — confirm the current PSI amount when you schedule, since CSLB no longer processes exam payments directly). You have 18 months from application acceptance to pass both exams before the application voids.

Bond and insurance: once you pass, CSLB requires a $25,000 contractor’s bond (LLCs also need a separate LLC employee/worker bond) before the license is issued, plus proof of workers’ compensation coverage if you have employees, or a signed Certificate of Self-Insurance/exemption if you work alone with no employees. An initial license activation fee is due at this stage as well.

For the full step-by-step walkthrough and a line-item cost breakdown, see our application guide and current fee and bond breakdown.

Class A vs. B, C-12, and C-34: Which License Do You Actually Need?

Class A vs. Class B (General Building): B covers construction of a structure requiring at least two unrelated trades to complete (framing, most residential and commercial buildings). Class A covers the civil/engineering works around and beneath that structure — grading the pad, running the utilities, building the retaining structure — but not the building itself. Many heavy-civil and site-development contractors hold both.

Class A vs. C-12 (Earthwork and Paving): C-12 is a narrower specialty limited to cuts, fills, excavation, grading, trenching, and paving. If earthmoving and paving is genuinely all you do, C-12 is the lower-barrier classification. Class A covers that same earthwork scope plus the broader engineering works (dams, pipelines, structural elements) that C-12 alone doesn’t authorize — choose Class A if your projects go beyond dirt and asphalt.

Class A vs. C-34 (Pipeline): C-34 is a specialty license for fabricating and installing pipelines that convey water, gas, or petroleum, including the trenching, boring, shoring, and backfilling needed to install them. Class A covers pipeline work as one piece of a larger general-engineering scope. If pipeline installation is your whole business, C-34 alone may be sufficient and easier to qualify for; if you also grade sites, build flood-control works, or handle roadwork, Class A is the broader fit.

Who Hires Class A Contractors

Typical clients are public agencies and large private developers rather than individual homeowners: county and municipal public-works departments, water districts and flood-control agencies, Caltrans and regional transportation authorities, utility companies, and land developers who need mass grading and underground infrastructure installed before a subdivision or commercial project can break ground. Many Class A firms compete for public-works bids, which often require prequalification, prevailing-wage compliance, and bonding capacity well above the CSLB minimum.

Class A FAQ

Can a Class A contractor build a house or commercial building?

Not under Class A alone. General building construction requiring two or more unrelated trades falls under Class B. A Class A contractor performing site grading and utilities for a project would typically pair with, or also hold, a Class B license for the vertical building work.

Do I need a separate license for each type of engineering work — dams, roads, pipelines?

No. Class A is a single classification that covers the full range of fixed-works engineering categories listed in B&P Code Section 7056. You don’t need C-12, C-34, or other specialty licenses in addition to Class A to perform work that falls within Class A’s scope, though some contractors carry both for flexibility on smaller specialty-only bids.

Is the Class A trade exam harder than the specialty (C-class) exams?

CSLB doesn’t rank exam difficulty, but Class A’s content spans eight distinct technical areas — from structural principles to piping to safety — versus a single-scope specialty exam, so most candidates find it demands broader preparation even if the format (multiple-choice, 3.5 hours, closed-book) is identical.

Can my four years of experience come from working as an engineer instead of a contractor?

Yes, qualifying experience can come from work as a journeyman, foreman, supervising employee, or contractor, and CSLB will also credit relevant technical education or apprenticeship training toward up to three of the four required years — but at least one year must be practical, hands-on experience that a certifier can verify.

Does a Class A license let me bid on Caltrans or public-works contracts?

Class A is the classification most public agencies expect for heavy-civil work, but bidding on public-works contracts also typically requires separate items like DIR public-works contractor registration and prevailing-wage compliance — the CSLB license is necessary but not the only requirement.

How long is my Class A license valid before I need to renew?

CSLB contractor licenses run on a two-year renewal cycle, the same as every other classification; you’ll need to keep your bond and workers’ comp coverage current throughout.

What happens if I fail the Class A trade exam?

You can retake it, but you’re still bound by the 18-month window from your original application acceptance date to pass both required exams, and each retake sitting requires its own PSI scheduling and testing fee.

Does the 2025 exam content update change what I should study?

CSLB’s current General Engineering (A) study guide (effective for exams scheduled on or after February 1, 2025) is the version reflected above. If you’re studying from an older guide or a third-party course last updated before 2025, confirm the section weightings still match — Safety, for example, is weighted at 18% in the current version.