C-33 Painting and Decorating exam questions, with answers

10 practice questions for the CSLB Painting and Decorating trade exam, each with the answer, a plain explanation and the source it rests on.

From our free C-33 test · Updated 14 October 2026

These are not real exam questions. CSLB does not release its test questions or answer keys, and nobody else has them. We write our own questions from the C-33 outline and the codes, standards and references CSLB lists for the exam. Each answer names its source so you can check it.

The C-33 exam has 4 sections. The questions below are grouped by section, with the share of the exam each one carries. Read the question, pick an answer, then open “Show the answer”. The other questions of the free test, scored section by section, are in the free 25-question C-33 test.

Planning and Estimating · 28% of the exam

Evaluating job sites; selecting tools, equipment and materials; selecting paint, stain and finish colors and products; reading blueprints and specifications; estimating job costs for materials, supplies, equipment and labor.

1. You are asked to bid four paid repaint jobs, and each one includes scraping and sanding old paint. According to EPA's lead-safe renovation (RRP) guide, which building's construction date means you must be certified and follow lead-safe work practices?

  1. A house built in 2003
  2. A house built in 1972
  3. A house built in 1984
  4. A condominium built in 1991
Show the answer

Answer: B. EPA's guide says contractors working for pay in homes or child-occupied facilities built before 1978 must be certified and follow lead-safe work practices. Only the 1972 house is older than that cutoff. The year the building was built is one of the first things to check on a site visit, because it changes the prep method, the containment and the price.

Source: EPA, Steps to Lead Safe Renovation, Repair and Painting (2026), introduction: 'Are you a professional renovator?'

2. Your pressure washer comes with four high-pressure quick-connect nozzles: 0°, 15°, 25° and 40°. The old paint on the siding is sound, and you only need to rinse it before repainting. Which nozzle gives the widest fan and is the one intended for rinsing painted or delicate surfaces?

  1. The 0° nozzle
  2. The 15° nozzle
  3. The 25° nozzle
  4. The 40° nozzle
Show the answer

Answer: D. The 40° (white) nozzle gives a wide fan for cleaning and rinsing painted or delicate surfaces. The 0° nozzle puts all the force on one spot and can cut into soft materials, and the 15° nozzle is for intense cleaning and for knocking off loose paint. The larger the angle, the more the force is spread out.

Source: Standard trade practice (Simpson pressure washer nozzle guide, white 40° nozzle)

3. On a finish plan, a thin line with an arrowhead runs from the note "PT-3, semi-gloss" to one wall of a room. What is this line, and what does it tell you?

  1. A dimension line; it gives the length of that wall
  2. A hidden line; it shows an edge that cannot be seen
  3. A center line; it marks the middle of the room
  4. A leader; it ties the note to the wall it points to
Show the answer

Answer: D. A leader is a thin line that points to the part of a drawing that a note explains, so the note applies to the wall the arrow touches. A dimension line shows a size and ends at extension lines, a hidden line is dashed, and a center line marks the center of a hole or a symmetrical object.

Source: Standard trade practice (Basic Blueprint Reading, Unit 1: leader line, dimension line, hidden line, center line)

Substrate Repair and Surface Preparation · 30% of the exam

Identifying problems; scraping, sanding and wallpaper removal; patching, caulking and repairing; masking and protecting job sites; removing paint and cleaning surfaces; applying primer.

4. Three years after a house was painted deep blue, the south and west walls look much lighter than the same paint under the eaves and on the north wall. The film is sound, and nothing rubs off on your hand. What is the problem?

  1. Fading: sunlight has lightened the color on the exposed walls
  2. Mildew: growth has discolored the sunny walls
  3. Efflorescence: salts have come out of the siding
  4. Surfactant leaching: soap-like residue has dried on the film
Show the answer

Answer: A. Fading is premature or excessive lightening of the color on sunny exposures, and it is easy to recognize because protected areas such as eaves usually do not fade. Mildew shows as dark spots in damp, shaded places. Efflorescence is a white salt deposit on masonry, and surfactant leaching leaves sticky or glossy streaks soon after painting.

Source: Standard trade practice (Sherwin-Williams Problem Solver, Fading)

5. You scraped flaking paint (tested lead-free) from an interior plaster wall. The old paint is many layers thick, so even after the edges are sanded the scraped spots still show as shallow craters. What gives a uniform surface for the new paint?

  1. Roll on two extra-heavy finish coats so the paint fills the craters
  2. Level the low spots with spackling compound, sand smooth, and prime
  3. Wire-brush the crater edges until they are rough, then paint
  4. Run a bead of caulk around each crater and paint over it the same day
Show the answer

Answer: B. After loose paint is scraped and the edges are feathered by sanding, flaking through several layers may still leave a step; a spackling compound is used to make the surface uniform, and bare plaster is primed before repainting. Heavy finish coats sag and still show the craters, and caulk or roughened edges do not level the wall.

Source: Standard trade practice (Sherwin-Williams Problem Solver, Cracking)

6. A painter runs a paintable acrylic caulk into the joints of new window trim and paints over the beads 15 minutes later, while the caulk is still soft. A week later the paint over the beads is cracked, but the caulk itself is not torn and is still stuck to both sides of each joint. What happened?

  1. The caulk was a pure silicone, which paint cannot stick to
  2. The caulk bonded on three sides and tore down the middle
  3. The paint dried first; the caulk then shrank as it dried and cracked it
  4. The paint was applied below its minimum temperature and never formed a film
Show the answer

Answer: C. When paint goes over a partly dried bead of caulk, the paint dries first and forms a film; as the caulk dries, it shrinks, stretches that film and cracks it. The cure is to let the caulk dry as its label directs before painting. The stem rules out the other causes: the caulk is a paintable acrylic and it is intact and still bonded to both sides.

Source: Standard trade practice (Sherwin-Williams Problem Solver, Caulk - Paint Cracking or Crawling)

Application of Paint, Wallcoverings, and Finishes · 21% of the exam

Applying paint and wallcoverings to surfaces; applying waterproofing or sealant; staining, sealing and finishing wood surfaces; applying touch-ups and cleaning work areas.

7. A strip of wallpaper is in position on the wall along the plumb line. In which direction should you work the smoothing brush to remove air pockets and wrinkles?

  1. From both edges in toward the center of the strip
  2. Only up and down along the seam, leaving the rest to flatten as it dries
  3. From the center of the strip outward toward the edges
  4. From the bottom upward, pulling hard to stretch the strip
Show the answer

Answer: C. Hanging instructions say to smooth the whole strip from the center outward, which pushes the air and extra paste out at the edges. Working from the edges inward traps air in the middle, and pulling hard stretches the paper, so the seams open when it dries.

Source: Standard trade practice (Brewster, How to Hang Unpasted Wallpaper; York SureStrip hanging instructions, step 8)

8. You are about to gun an acrylic latex sealant into a 1/4-inch joint around exterior window trim. How should the nozzle of the cartridge be cut?

  1. Straight across at the base of the nozzle, for the fastest flow
  2. At a 45-degree angle, at the point that gives the needed bead size
  3. Not at all; pierce the side of the nozzle with a nail instead
  4. Straight across at the very tip, whatever the width of the joint
Show the answer

Answer: B. Sealant data sheets say to cut the nozzle at a 45-degree angle to the desired bead size. The angled opening rides along the joint, and cutting at the right point on the tapered nozzle sets the bead width. Cutting at the base gives a bead far too large for a 1/4-inch joint, and a tip cut that ignores the joint width gives the wrong bead.

Source: Standard trade practice (DAP Dynaflex 230 data sheet, application step 3; DAP latex window glazing bulletin)

Safety · 21% of the exam

Tool and equipment safety; personnel and job site safety; environmental safety; handling hazardous materials; Cal/OSHA safety requirements.

9. California city stormwater programs tell painting contractors never to let paint or wash water run into a street gutter or storm drain. According to these programs, what is the main reason?

  1. Storm drains lead to the sewage treatment plant, which cannot process paint
  2. Storm drains are too small, and paint solids block them within days
  3. Storm drains are private property, so a discharge fee would be owed
  4. Storm drain flows are not treated and go straight into local waterways
Show the answer

Answer: D. The sanitary sewer carries wastewater to a plant where it is treated, but the storm drain system does not: what enters a gutter or storm drain is released untreated into local creeks and other waterways. That is why paint, chips and wash water must be kept out of the street, the gutter and the drain.

Source: City of Roseville, Painting Contractors BMP fact sheet – Sanitary Sewer vs. Storm Drains

10. Your crew is spending the whole week spraying a solvent-based lacquer at one job site across town from your shop. Under Cal/OSHA's Hazard Communication standard (§5194), where must the safety data sheet (SDS) for the lacquer be?

  1. On file at the shop office, to be sent to the job within one business day
  2. With the paint supplier, who must provide it when an employee asks
  3. Readily accessible to the employees in their work area during each work shift
  4. In the foreman's locked truck, to be shown only after an exposure incident
Show the answer

Answer: C. Section 5194 requires the employer to keep safety data sheets for each hazardous chemical in the workplace and to make sure they are readily accessible during each work shift to employees when they are in their work areas. Electronic access is allowed only if nothing blocks immediate access. A sheet kept across town or locked away does not meet the rule.

Source: 8 CCR §5194(g)(8), Cal. Code Regs., Title 8, §5194 Hazard Communication

Where to go from here

How the license works, from experience to fees: how to get a C-33 license. Everything about the course: the C-33 exam page.

Questions from our free C-33 test, written from CSLB License Examination Study Guide, Painting and Decorating (C-33), form 13E-33 (03-2026). CSLB notes that the percentages are approximate. Reviewed 14 October 2026. Study guidance only; we are not affiliated with CSLB or PSI.

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