CSLB C-27 Landscaping Trade Exam Study Guide (2026)

Two contractors bid the same backyard. One prices the work, signs a one-page proposal, takes half down, and starts trenching Monday. The other prices the work, subcontracts the new 120-volt circuit for the controller, writes a contract with the required cancellation notice, collects a legal deposit, and calls 811 on Thursday for a Monday dig.

Both can build a beautiful yard. Only one still has a license in five years.

1.1 What the C-27 License Authorizes

The C-27 classification is defined at 16 CCR §832.27. Read the regulation itself once — it is a single paragraph and it is the source of every scope question on this exam. In substance: a landscaping contractor constructs, maintains, repairs, installs, or subcontracts the development of landscape systems and facilities for public and private gardens and other areas designed to improve the grounds within or surrounding a structure or a tract or plot of land — aesthetically, architecturally, horticulturally, or functionally. In connection with that work, the landscaping contractor prepares and grades plots and areas of land for the installation of any architectural, horticultural, and decorative treatment or arrangement.

Three phrases do most of the work on the exam:

"Landscape systems and facilities." Irrigation, drainage, planting, turf, low-voltage landscape lighting, decorative water features, garden walls, patios, walks, and the grading that makes them work.

"Prepares and grades plots and areas of land." Grading for landscape purposes is expressly inside the classification. That is why "grading and preparing a yard for decorative treatment" is a clean C-27 answer, paired against three items that are clearly somebody else's work.

"Or subcontracts." The classification anticipates that you will run jobs containing work outside it and hire licensed subcontractors for that work. Subcontracting is not weakness — it is the mechanism the licensing law gives you.

1.2 Where the C-27 Line Is — Four Boundaries That Get Contractors Cited

This is the highest-value section in the book relative to its length. Scope questions appear in every chapter, and candidates miss them because the wrong answer feels reasonable on a job site. "The trench is already open." "It's only fifty feet of cable." "It's in the landscape area." None of those extend a classification.

Boundary 1 — Electrical. The line is line voltage versus low voltage. Setting a transformer that plugs into an existing, code-compliant exterior receptacle and running low-voltage cable to the fixtures is landscape work. Running 24-volt valve wire from a controller to a solenoid is landscape work. Installing a new 120-volt branch circuit, adding a receptacle, or setting a subpanel is electrical work — no matter how short the run, whether you sleeve it in conduit, or whether an inspector will look at it later. If the new controller location has no power, the answer is a licensed electrical contractor.

Boundary 2 — Plumbing and the point of connection. Your system begins at the point of connection on the service. Everything downstream — mainline, backflow assembly, valves, laterals, heads, drip — is landscape work. The potable water service supplying the building, and the plumbing inside it, is not. When a homeowner watches your crew trench for irrigation and asks you to replace the corroded service line from the meter to the house, decline or subcontract it. The open trench is not the test; the classification is.

Boundary 3 — Engineered retaining walls. A low garden wall retaining landscape soil is landscape work. Under the California Building Code, a retaining wall generally becomes permit-required once it exceeds about four feet measured from the bottom of the footing to the top of the wall, and at any height if it supports a surcharge — a driveway, a structure, or a slope above it. (That figure is code-cycle-dependent and jurisdictions amend it; confirm locally.) Past that line it needs an engineered design, a permit, and someone qualified to build to that design. Stacking three-foot terraces does not dodge engineering if the upper wall surcharges the lower one; an owner's waiver does not remove a code obligation; an inspection after the fact does not substitute for a design before it.

Boundary 4 — Structures, pools, roofs, trees. A wood-framed pool house with a bathroom is a habitable structure with plumbing and electrical work in it, not a landscape facility — and being inside the landscape area or under the contract value does not make it one. Swimming pool construction (C-53), roofing (C-39), and in many contexts tree service (D-49) are separate classifications. Subcontract what you are not licensed for.

The exam's favourite distractors are all versions of one wrong idea: that a fact about the job can extend a classification. Location inside the landscape area, dollar value, an open trench, an existing tee, a matching pipe size, who pulls the permit, or a homeowner's consent — none of these change what your license authorizes.

1.3 Reading the Plan and Taking Off Quantities

Scale. Figure out how many feet one inch represents, then multiply. At 1 inch = 10 feet, a bed measuring 4 inches on the plan is 40 feet. At 1/8 inch = 1 foot, each inch represents 8 feet, so a wall measuring 5 inches is 40 feet. The classic error is dividing when you should multiply — and the exam always offers that answer.

The legend and plant schedule. A schedule entry such as QUAG, 24" box, 7 reads as three fields: abbreviated botanical name, container size, quantity. Read the "24" as the count and the whole takeoff is wrong. And price from the plans and specifications together — plans give geometry and location, specifications give materials and installation standards. Neither alone is enough, and a verbal description from the owner is not a basis for a binding price.

Areas. Rectangle: L × W. Triangle: ½ × base × height, so 18-foot base and 12-foot height is 108 sq ft — the exam offers 216, the full rectangle before halving. Circle: π r², using the radius, so a 12-foot-radius lawn is about 452 sq ft. Using the diameter where the radius belongs is the most common circle error.

Volumes. A cubic yard is 27 cubic feet:

cu yd = L(ft) × W(ft) × D(ft) ÷ 27, or cu yd = area(sq ft) × depth(inches) ÷ 324

because 12 × 27 = 324. A 24 × 15 bed at 4 inches of mulch is 360 × 4 ÷ 324 = 4.4 cu yd. Sold by weight instead? Multiply, don't divide: decomposed granite at 1.4 tons per cubic yard means 9 cu yd is about 12.6 tons.

Plant counts. At square spacing each plant occupies (spacing)². Thirty inches is 2.5 feet, so 6.25 sq ft per plant, and a 400 sq ft bed takes 64. Triangular spacing offsets rows so plants sit closer to diagonal neighbors: it fits more plants in the same area and closes the bed more evenly.

Waste and swell. Add waste to what you buy — roughly 5 to 10 percent on sod for cuts and curves, similar on concrete because subgrades are never flat and material spills. Add swell to what you haul away: excavated soil breaks its compacted structure and occupies more volume loose in the truck than in the ground.

1.4 Pricing the Job

Direct cost attaches to this job: materials delivered to it, equipment rental billed for days used on it, subcontracts performed on it, and direct labor — crew wages plus the burden riding on wages (payroll taxes, workers' comp premium). Overhead is the cost of being in business whether or not this job runs: office rent, general liability, vehicles. Contingency is a reserve for conditions you can anticipate in aggregate but not itemize. Profit is what the company earns for taking the risk.

Production rates convert scope into hours. At 250 sq ft of sod per crew-hour, a 3,000 sq ft lawn is 12 crew-hours. Use your own historical rates — they capture your crews, your equipment, your sites. Published rates describe someone else's company.

Markup versus margin. Markup is a percentage of cost. Margin is a percentage of price.

• 20 percent markup on a $10,000 cost gives $12,000 — a margin of about 16.7 percent.
• 20 percent margin means cost is 80 percent of price: $10,000 ÷ 0.80 = $12,500.

Job costing tells you whether any of it worked: actual labor, material, and subcontract costs set against the estimate line by line. Annual revenue against overhead measures the company; deposit history measures cash flow; neither measures the job.

1.5 The Contract, the Permits, and the Licensing Law

A written contract. A home improvement contract must be in writing and signed before work begins once the price passes a low statutory threshold — historically $500 under B&P §7159. An $18,000 landscape job is far past it. An estimate is not a contract, an oral agreement does not satisfy the requirement no matter who was standing there, and it does not depend on the owner asking for paper.

Down payment. Capped at $1,000 or 10 percent of the contract price, whichever is less (B&P §7159.5). On a $30,000 job the ceiling is $1,000 — not $3,000. Statutory figure; confirm the current cap.

Right to cancel. A three-day right of cancellation, disclosed in the agreement, with a longer period for certain senior homeowners. It is not tied to whether a deposit cleared, and a customer who called you first still gets the disclosure.

The minor-work exemption. B&P §7048 exempts small jobs from the license requirement when the total contract price for labor and materials combined falls under a statutory threshold. That threshold was $500 and was raised to $1,000 by AB 2622, subject to conditions in the statute. Two things are testable regardless of the current figure: the test is the aggregate price including materials, and the exemption is not limited to repairs. A $1,400 planter installed by an unlicensed neighbor is over any version of the line. Verify the current threshold and conditions.

Advertising. A licensee's license number must appear in advertising. The bond amount, the qualifier's name, and a list of classifications you could hold are not advertising requirements.

Bond and insurance. The license bond provides limited recovery to specified claimants harmed by a licensee's violation of the licensing law. It is not insurance for you: property damage is general liability, completion is a performance bond, employee injury is workers' compensation. Once you have employees, workers' compensation is mandatory and CSLB requires evidence of it. The exemption for licensees without employees is being phased out on a statutory schedule — confirm the current requirement with CSLB rather than assuming an exemption still applies.

Change orders. When the owner asks for an extra bed after signing, write a change order describing the work and the price, signed before the work is done. Adding it quietly and billing at the end is how contractors end up in small-claims court. Absorbing it is a gift with no recovery mechanism. Retention is money the owner holds, not a way to charge for extras.

Lien rights. A supplier or subcontractor with no direct contract with the owner preserves mechanics lien rights by serving a preliminary notice on the owner and lender early in the job. A notice of completion is recorded by the owner and starts a different clock; CSLB plays no role in lien rights.

Permits. Grading and a retaining wall go through the local building or engineering department; work in the public right of way requires an encroachment permit from the agency that owns it. There is rarely a blanket permit covering a mixed landscape scope, and landscape work is not automatically exempt. On the schedule, the constraint that most often drives the timeline is an inspection hold on work that must be inspected before it is covered — underground and grading. A missed or failed inspection stops everything downstream.

Key Numbers & Facts — Chapter 1 - 16 CCR §832.27 — landscape systems and facilities, plus preparing and grading plots; expressly contemplates subcontracting. - New 120V branch circuit / receptacle / subpanel → electrical contractor. Transformer at an existing receptacle + low-voltage runs → landscape. - Potable service to the building → plumbing contractor. Your work starts at the point of connection. - Retaining wall: permit + engineering generally over ~4 ft (footing to top), or ANY height with a surcharge — cycle-dependent, verify locally. - 1 cu yd = 27 cu ft. cu yd = area(sf) × depth(in) ÷ 324. Circle = π r² (radius!). Triangle = ½ b h. - Square spacing: plants = area ÷ (spacing)². Triangular fits MORE. - Markup is on cost; margin is on price. Price = cost ÷ (1 − margin). - Written home improvement contract above a low threshold (historically $500). Down payment: $1,000 OR 10%, whichever is LESS. Three-day right to cancel. Minor-work exemption raised $500 → $1,000 (AB 2622), aggregate price. All statutory — verify. - License number in advertising. License bond = limited consumer recovery, not insurance. - Change orders in writing, signed first. Preliminary notice preserves lien rights. Encroachment permit for the public right of way.