The California C-27 Landscaping Contractor license is issued by the Contractors State License Board (CSLB) and is required for anyone who contracts to install, maintain, repair, or improve lawns, gardens, ornamental plantings, and related outdoor structures valued at $500 or more in combined labor and materials. The license exam tests your knowledge of plant science, irrigation, landscape construction, pest management, business law, and California-specific regulations including water conservation and worker safety requirements.
Our free C-27 practice test PDF lets you study offline with a printable question set drawn from real exam topics. Print it, time yourself, and check the answer key to identify the areas where you need to strengthen your knowledge before test day.
The CSLB C-27 trade exam is one of the more comprehensive specialty contractor exams in California. It spans six major subject areas, each requiring both theoretical knowledge and practical application. The Law and Business exam, taken separately, tests California contractor license law, contract requirements, tax obligations, and worker safety regulations. You must pass both exams to obtain the license.
A significant portion of the trade exam tests plant science fundamentals. You need to identify common California landscape plants — trees, shrubs, ground covers, and ornamental grasses — by their common and scientific names. Expect questions on plant hardiness zones, water requirements (low, moderate, high), seasonal growth patterns, and plant spacing for mature size. Soil science questions cover soil texture classifications (sandy, loamy, clay), pH ranges and amendment practices, organic matter content, and how soil type affects irrigation scheduling and plant selection. Fertilizer chemistry — NPK ratios, slow-release versus quick-release formulas, soil testing interpretation, and nutrient deficiency symptoms — rounds out this section.
Irrigation is one of the most technically demanding areas on the C-27 exam. You must understand hydraulic principles — static pressure, dynamic pressure, pressure loss through pipe and fittings, and flow rate calculations. The exam tests drip irrigation system design, spray head spacing and precipitation rate matching, valve sizing, backflow preventer selection (atmospheric vacuum breaker vs. pressure vacuum breaker vs. reduced pressure assembly), and controller programming for seasonal water budgeting. California's water crisis has elevated smart controller and weather-based irrigation scheduling (ET-based systems) to a central exam topic. You should also know the differences between recycled water and potable water system requirements and color-coding standards.
Landscape construction questions cover site grading and drainage design, including positive drainage away from structures, swale sizing, French drain installation, and catch basin placement. Hardscape installation topics include paver and flagstone base preparation (compaction, aggregate depth, sand bed depth), concrete and masonry retaining wall design, slope stability limits, and load-bearing calculations for patio structures. You need to understand proper sub-base compaction standards, soil bearing capacity, and when engineered drawings are required under California Building Code. Timber and block retaining wall construction, including drainage behind walls, is regularly tested.
California has some of the strictest pesticide regulations in the nation. C-27 exam questions cover integrated pest management (IPM) principles — identification, monitoring, thresholds, and control strategies. You need to know the categories of pesticide licenses issued by the California Department of Pesticide Regulation (DPR): Qualified Applicator License (QAL), Qualified Applicator Certificate (QAC), and Pest Control Adviser (PCA). The exam tests pesticide label reading (the label is the law), signal words (Caution/Warning/Danger), restricted-entry intervals (REI), personal protective equipment (PPE) requirements, and proper pesticide storage and disposal under California law. Knowing when a pesticide applicator license is required — separate from the C-27 — is a common exam question.
The Model Water Efficient Landscape Ordinance (MWELO), adopted under California's AB 1881 and updated in 2015, is mandatory knowledge for the C-27 exam. MWELO applies to new construction and rehabilitated landscapes above a certain square footage threshold (500 sq ft for commercial, 2,500 sq ft for residential in most jurisdictions). Key requirements include a maximum applied water allowance (MAWA) calculation, plant factor selection using the WUCOLS database, irrigation efficiency standards, a soil management plan, and a landscape documentation package submitted to the local agency. Post-installation irrigation audits and maintenance schedules are also covered. Candidates who understand MWELO structure and calculations have a clear advantage on this section of the exam.
The Law and Business exam covers California contractor license law under Business and Professions Code Sections 7000–7191. Topics include the $500 threshold that triggers licensing requirements, contract requirements (written contracts for projects over $500 with specific required clauses), mechanics lien law, stop payment notices, payment bond requirements, and the CSLB disciplinary process. Business management questions cover payroll tax obligations (EDD, FTB), workers compensation insurance requirements, safety violation penalties, and surety bond requirements. You must also know the CSLB application process, qualifying individual requirements, and license classification boundaries — specifically, what a C-27 can and cannot do versus adjacent classifications like C-57 (Well Drilling) or C-61 (Limited Specialty).
California's heat illness prevention standard (Title 8 CCR Section 3395) is mandatory exam material. It requires employers to provide shade when temperatures exceed 80°F, potable water (1 quart per hour per worker), a written heat illness prevention plan, and emergency response procedures. Recovery periods (at least 5 minutes in shade when a worker believes heat illness is developing) and high-heat procedures (mandatory buddy system and pre-shift meetings when temperatures reach 95°F) are specifically tested. Cal/OSHA's Injury and Illness Prevention Program (IIPP) requirements, forklift and equipment operation safety, and underground utility locating requirements (California's DigAlert/811 system and the 72-hour advance notice rule) round out the safety section.
Need more practice with instant scoring? Our C-27 landscaping contractor practice test covers plant science, irrigation, MWELO, pest management, and California contractor law with full answer explanations. Use the online tests alongside this PDF to build speed and confidence before your CSLB exam.