📋 Exam: C-36 Plumbing
Questions: 120+
Exam Time: 3 hrs

Pass the California
C-36 Plumbing
License Exam

This is your complete, interactive prep course built directly from the CSLB C-36 Study Guide. Five exam sections, 120+ real-style questions, formula calculators, flashcards, and a 10-week study plan — everything you need to pass the first time.

📝
~100
Exam Questions
3 HRS
Time Allowed
🎯
70%
Passing Score
📖
Closed
Book Policy

📋 Exam Section Breakdown

The C-36 exam covers 5 sections. Know exactly where to focus your time:

📚 Quick Tips from CSLB

Multiple Choice — 4 options, 1 BEST answer

Read all four options completely before choosing. CSLB writes questions where multiple answers may seem right — you need the BEST one.

No penalty for guessing — always answer every question, even if unsure.
A calculator is provided for math problems.
This is a CLOSED-BOOK exam. No reference materials allowed during the test.

🔑 Key Reference Codes (Know These Cold)

2022 CA Plumbing Code

Primary code — pipe sizing, venting, fixtures. Published by IAPMO. Title 24.

2022 CA Building Code

Structural & inspection requirements. ICC. Title 24.

2022 CA Mechanical Code

Fuel gas, HVAC overlap, mechanical systems. IAPMO. Title 24.

Cal/OSHA Title 8

Safety orders — all personnel, job site, trenching, confined space.

CA Green Building Code

Water conservation requirements. CALGreen. Title 24.

Underground Service Alert

Call 811 before digging. CA Govt Code 4216. Mandatory notification.

Exam Overview

The C-36 Plumbing Exam is divided into five major sections. Each section carries a specific weight — your study time should reflect these percentages.

01

Planning & Estimating

22%
  • Scope of work & code compliance
  • Pipe sizing & venting requirements
  • Shop drawings, plans & specifications
  • Job site inspections
  • Water conservation
  • Cost estimation (materials, labor, overhead)
02

Underground & Rough Systems

22%
  • Excavation & underground installations
  • Piping layout & installation
  • Fuel gas piping
  • Insulation & system testing
03

Finish Plumbing Installations

20%
  • Plumbing fixtures & appliances
  • Water heaters
  • Shut-off valves
  • Specialty installations
  • Industrial & commercial piping
04

Service, Repair & Remodel

19%
  • Troubleshoot plumbing issues
  • Isolate leaks & damage
  • Repair plumbing systems
  • Retrofit plumbing
  • Disposal of plumbing materials
05

Safety

17%
  • Personnel safety (Cal/OSHA Title 8)
  • Job site safety
  • Environmental safety
  • Trenching & shoring
  • Confined space entry

🗓 What to Expect on Exam Day

Format

  • Multiple-choice, 4 options per question
  • Only one BEST answer
  • Some questions require math computation
  • Calculator is provided by testing center
  • No penalty for guessing

Logistics

  • Administered at PSI testing centers statewide
  • Closed-book — no reference materials
  • Approx. 3 hours to complete
  • You must also pass the Law & Business Exam
  • Bring government-issued photo ID
The exam is written and reviewed by licensed plumbing contractors who are actively working in the trade — so questions are grounded in real-world application, not just textbook theory.
Planning & Estimating

Covers scope of work, code compliance, pipe sizing/venting, shop drawings, inspections, project coordination, water conservation, and cost estimation.

📐 Scope of Work & Code Compliance

Before any plumbing work begins, the contractor must establish the scope of work — what is covered under the C-36 license — and ensure full compliance with applicable codes.

The C-36 license covers: water supply systems, drain/waste/vent (DWV) systems, fuel gas piping, water heaters, and related fixtures on residential, commercial, and industrial projects.

Know the difference between C-36 (Plumbing) and adjacent licenses: C-20 (HVAC), C-34 (Pipeline), C-42 (Sanitation). Overlap questions appear on the exam.

2022 CA Plumbing Code § 101 — General scope and authority. All plumbing must conform to the California Plumbing Code (CPC), Title 24.

🔢 Pipe Sizing — The Core Formula

Pipe sizing is one of the most tested math topics. It's based on Drainage Fixture Units (DFU) and Water Supply Fixture Units (WSFU).

DFU = Sum of fixture unit values for all fixtures served by that drain

Common Fixture Unit Values (DFU):
• Lavatory (sink): 1 DFU
• Bathtub / Shower: 2 DFU
• Water Closet (toilet): 4 DFU (private) / 6 DFU (public)
• Kitchen Sink (residential): 2 DFU
• Washing Machine: 2 DFU
• Floor Drain: 2 DFU
• Urinal: 4 DFU

2022 CPC Table 7-3 — Drainage fixture unit values. CPC Table 6-4 — Water supply fixture units.

For sizing a building drain: total all DFUs on the system and refer to CPC Table 7-5 for minimum pipe diameter. A 4" drain handles up to 160 DFU.

🌬 Venting Requirements

Every fixture trap must be vented. Venting prevents siphoning of trap seals and allows air circulation through the DWV system.

  • Minimum vent pipe size: 1¼" — never smaller than the drain it serves (up to 4")
  • Individual vent: connects above the trap weir to the main vent stack
  • Common vent: two fixtures back-to-back sharing one vent
  • Wet vent: serves as both a vent and a drain for a fixture
  • Air Admittance Valve (AAV): allowed under CPC for isolated locations — must be accessible
  • Trap-to-vent distance: varies by pipe size; 2" trap arm max 5 ft to vent

2022 CPC Chapter 9 — Venting systems. Critical chapter — memorize the trap arm distances.

📊 Shop Drawings & Plans

The contractor must be able to read and interpret plumbing plans, isometric drawings, and specifications.

  • Isometric drawings show 3D pipe runs in 2D — used for DWV and supply layout
  • Plan view = overhead view showing pipe routing on each floor
  • Riser diagrams show vertical pipe routing through building floors
  • Specifications (specs) define materials, quality standards, and installation methods
On the exam: be able to read a simple isometric drawing and identify pipe sizes, fixture locations, and venting paths.

💧 Water Conservation (CALGreen)

California's Green Building Standards Code (CALGreen) mandates maximum flow rates for plumbing fixtures:

Showerheads: max 1.8 GPM @ 80 psi (residential, effective 2018)
Lavatory faucets: max 1.2 GPM (residential) / 0.5 GPM (public restrooms)
Kitchen faucets: max 1.8 GPM
Water closets: max 1.28 GPF (high-efficiency, HET)
Urinals: max 0.5 GPF (HEU)

CALGreen § 4.303 — Residential indoor water use. CALGreen § 5.303 — Nonresidential indoor water use.

💰 Cost Estimation

The exam tests your ability to calculate job costs including materials, labor, equipment, and overhead.

Total Job Cost = Materials + Labor + Equipment + Overhead + Profit

Labor Cost = Hours × Hourly Rate
Equipment Cost = Days × Daily Rate
Overhead = typically 10–20% of direct costs

Example (from official CSLB sample):
Backhoe rental: $400/day × 4 days = $1,600
Operator: $70/hr × 8 hrs × 4 days = $2,240
Total = $1,600 + $2,240 = $3,840 ✓
Always calculate equipment and labor separately, then add them. This is a common exam trap — don't double-count or confuse the rates.
Underground & Rough Systems

Covers excavation, underground pipe installations, piping layout, fuel gas piping, insulation, and system testing.

⛏ Excavation & Underground Safety

Always call 811 (Dig Alert / Underground Service Alert) before any excavation. California law (Gov. Code 4216) requires notification at least 2 working days before digging — except in emergencies.

  • Trenches 5 ft or deeper require a protective system (shoring, sloping, or shielding)
  • Soil types (A, B, C) determine allowable slope angles — Type C is the most unstable
  • Type C soil: slope 1½H:1V (34°) maximum
  • Type B soil: slope 1H:1V (45°) maximum
  • Type A soil: slope ¾H:1V (53°) maximum
  • A competent person must inspect the trench daily and after rain

Cal/OSHA Title 8 §1541 — Excavations. Critical for the Safety section too.

🔩 Underground Pipe Installation

Underground drainage piping must be properly bedded and protected. Key requirements:

  • Minimum cover over sewer pipe: 12 inches (residential) under slabs
  • Minimum slope for drainage: ¼" per foot (2%) for pipes up to 3"; ⅛" per foot (1%) for pipes 4" and larger
  • Under-slab material: ABS or PVC Schedule 40 are most common; cast iron also accepted
  • Pipe bedding: granular material (pea gravel or sand) min. 4" under pipe in unstable soil
  • Building sewer separation: minimum 5 ft from water service laterals (10 ft preferred)
Slope Calculation:
Drop = Length × Slope
Example: 20 ft of 3" pipe at ¼"/ft = 20 × 0.25 = 5" total drop

2022 CPC § 722 — Underground drainage. CPC § 724 — Pipe bedding.

🔥 Fuel Gas Piping

Natural gas and LP gas piping falls under C-36 scope. Key code points:

  • Gas piping must be sized for the BTU demand of all connected appliances
  • Approved materials: black steel (Schedule 40), CSST (corrugated stainless steel tubing — must be bonded), or approved PE for underground
  • All gas piping must be tested at 1½ times working pressure or 3 psi, whichever is greater, for a minimum of 10 minutes before being covered
  • Gas shutoff must be within 6 ft of appliance (or per local AHJ)
  • CSST bonding: required per CPC and NEC 250.104(B) — ½" or larger bonding conductor

2022 CPC Chapter 12 — Fuel gas piping systems. 2022 CA Mechanical Code Chapter 13 — Gas piping.

CSST (yellow flexible gas piping) MUST be bonded to the electrical grounding system. Failure to bond is a code violation and a fire hazard.

🧊 Insulation Requirements

Pipe insulation is required by the California Energy Code (Title 24, Part 6) for hot water supply and recirculation lines to reduce heat loss.

  • Hot water supply pipes inside conditioned space: minimum R-3 insulation if ¾" or larger
  • Cold water pipes in unconditioned spaces or below grade: insulate to prevent condensation and freezing
  • Domestic hot water recirculation lines: must be insulated per CEnC Table 150.0-B

CA Energy Code § 150.0(j) — Piping insulation requirements.

🔍 System Testing Requirements

All new plumbing systems must be tested and inspected before concealment. Common tests:

Water Test (DWV): Fill system with water to the highest point.
Hold for minimum 15 minutes with no leaks. (CPC § 723.0)

Air Test (DWV): Pressurize to 5 psi (not more than 6 psi).
Hold for minimum 15 minutes. (CPC § 723.0)

Water Supply Test: 100 psi for 15 minutes, or
1.5x working pressure — whichever is greater.

Gas Piping Test: 1.5x working pressure or 3 psi min.
Hold for 10 minutes with no pressure drop.
For the exam: water test uses the system itself as the gauge. Air tests use an air compressor and gauge. Know both methods and their minimum pressures/hold times.
Finish Plumbing Installations

Covers plumbing fixtures, appliances, water heaters, shut-off valves, specialty installations, and commercial/industrial piping.

🚿 Plumbing Fixtures — Installation Standards

All fixtures must be listed and labeled (UPC/ANSI approved) and installed per the CPC. Key requirements:

  • Water closet rough-in: standard is 12" from finished wall to center of drain (also 10" and 14" available)
  • Wall-mounted water closet: requires an approved carrier fitting (NOT a hubless closet ring) — this is an official CSLB sample question
  • Clearances — water closet: 15" min from centerline to any side wall or obstruction; 21" clear in front (residential), 30" preferred
  • Lavatory: P-trap required; max 24" developed length from trap weir to vent
  • Shower pan liner: must be water-tested for 24 hours with no leakage before tile installation
  • Bathtub overflow: must connect to drain line before the P-trap

2022 CPC Chapter 4 — Plumbing fixtures and fixture fittings.

🌡 Water Heaters

Water heater installation is heavily tested. Key code requirements:

  • T&P (Temperature & Pressure) Relief Valve: required on every water heater; discharge pipe must terminate 6" from floor (or to approved drain), must not be reduced in size, minimum ¾" ID
  • GFCI protection: required for electric water heaters in garages
  • Seismic strapping: California requires TWO straps — one in upper ⅓, one in lower ⅓ of tank
  • Pressure relief: set at 150 psi maximum
  • Temperature setting: 120°F maximum (to prevent scalding, per CPC)
  • Expansion tank: required when a check valve or PRV is installed on the supply side (closed system)
  • Clearances: 18" from floor in garage if gas (to keep pilot above combustibles)

2022 CPC § 501–508 — Water heater requirements.

Never cap or reduce the T&P relief valve discharge pipe. This is the most common code violation — and a life-safety issue.

🔒 Shut-Off Valves

Isolation valves allow portions of the system to be serviced without shutting off the entire building water supply.

  • Main shut-off: required at the water service entrance to every building
  • Individual fixture shut-offs: required under every sink, toilet, and at each water-using appliance
  • Pressure Reducing Valve (PRV): required when supply pressure exceeds 80 psi; set to 60–80 psi
  • Hose bibb vacuum breaker: required on all hose connections to prevent backflow
  • Backflow prevention: required at cross-connection points; type depends on hazard level (AVB, PVB, DCVA, RPZ)

2022 CPC § 603 — Water supply valves. CPC Chapter 6 — Cross-connection control.

🏭 Commercial & Industrial Piping

Commercial plumbing involves larger systems, grease interceptors, and specialty systems:

  • Grease interceptors: required for restaurants and food service facilities; sized in GPM based on fixture flow rates; typically 40–100 GPM units
  • Interceptor sizing formula: GPM = (Fixture capacity in gallons ÷ drainage time in minutes) × drain factor
  • Floor drains in commercial kitchens: must connect to grease interceptor, not directly to sewer
  • Reduced pressure zone (RPZ) backflow preventer: required for high-hazard cross-connections (boilers, irrigation, etc.)
  • Medical gas: not covered by C-36; requires specialty contractor
Grease Interceptor Sizing Example:
3-compartment sink: 3 × 20 gal = 60 gal capacity
Drainage time: 1 minute (typically used)
Drain factor: 0.75 (for food waste)
GPM = (60 ÷ 1) × 0.75 = 45 GPM → Use next size up: 50 GPM interceptor

💧 Water Filtration

Filtration systems remove contaminants from domestic water. Know the filtration media:

  • Carbon (activated charcoal): used for taste and odor control — this is the CSLB official sample question answer
  • Sand/multimedia filters: remove sediment and turbidity
  • Water softeners (ion exchange): remove calcium and magnesium (hardness)
  • UV treatment: kills bacteria and viruses without chemicals
  • Reverse osmosis (RO): removes dissolved solids, heavy metals

2022 CPC § 611 — Water treatment devices.

Service, Repair & Remodel

Covers troubleshooting plumbing issues, isolating leaks, making repairs, retrofitting systems, and proper disposal of materials.

🔍 Troubleshooting Plumbing Issues

The exam tests real-world diagnostic skills. Common problems and causes:

  • Slow drains: partial blockage, improper slope, trap vaporization (check vent)
  • Gurgling drains: inadequate venting — negative pressure pulling water from traps
  • Water hammer: sudden pressure spike from fast-closing valves; cure with air chambers or water hammer arrestors
  • No hot water: pilot outage (gas), failed heating element (electric), or T&P valve has discharged (pressure issue)
  • Running toilet: worn flapper, misadjusted float, or cracked overflow tube
  • Low water pressure: partially closed valve, failing PRV, mineral buildup, undersized supply line, or high demand
  • Sewer gas odor: dry trap, cracked pipe, or failed wax ring

🔦 Isolating Leaks & Diagnosis

Systematic isolation is key to efficient repair:

  • Start by shutting off the main and checking if meter is still moving (indicates a leak downstream)
  • Use zone shut-offs to narrow the leak location section by section
  • Pressure testing with gauges helps identify leak rate and location
  • Electronic leak detection (acoustic sensors) for concealed pipe leaks
  • Camera inspection (CCTV) for underground drainage problem diagnosis
If a water meter is still spinning with all fixtures off and valves closed to the building, the leak is on the service lateral between the meter and the building.

🔧 Repair Methods

Know the correct repair method for each pipe material:

  • Copper pipe: solder (sweat) joints, compression fittings, or push-fit connectors (SharkBite-type)
  • PVC/ABS: solvent cement — purple primer required before cement on PVC; ABS uses black cement
  • Cast iron: hubless couplings (Fernco/rubber), or lead and oakum for hub joints (legacy)
  • Galvanized steel: threaded fittings; or cut-out and replace with approved materials
  • CPVC: CPVC-specific cement only; do NOT use PVC cement on CPVC
  • PEX: crimp rings, clamp rings, or expansion fittings — never solvent-welded

2022 CPC Chapter 6 & 7 — Approved pipe materials and joining methods.

🏗 Retrofit & Remodel Plumbing

Remodel work requires understanding code requirements for existing systems:

  • When remodeling, new work must meet current code even if existing system does not
  • California low-flow mandate: any toilet replacement must be 1.28 GPF or less (HET)
  • Re-piping: whole-house repipe with PEX or copper is common; requires permit and inspection
  • Earthquake retrofits: add flexible connectors at water heater and gas appliances
  • Drain relining (CIPP): cured-in-place pipe lining can repair underground sewer without excavation — must be approved by AHJ
Always pull a permit for remodel plumbing. Unpermitted work can result in license revocation under CSLB. Cal B&P Code § 7028 — performing work without a permit is a violation.

♻️ Disposal of Plumbing Materials

Proper disposal of old plumbing materials is legally required:

  • Lead pipe/solder: classified as hazardous waste; must go to a certified hazardous waste facility
  • Asbestos pipe insulation: asbestos abatement required by a licensed asbestos contractor before removal
  • Refrigerants (from water chillers): EPA Section 608 certified technician required for recovery
  • Used oil (compressor oil): must be recycled; not disposed in sewer or trash
  • PVC/ABS scrap: recyclable — separate from general trash at certified recyclers

Cal/OSHA & Cal/EPA — Hazardous material disposal regulations.

Safety

Covers personnel safety, job site safety, and environmental safety — all governed primarily by Cal/OSHA Title 8.

👷 Personnel Safety — Cal/OSHA Title 8

Every plumbing contractor must know Cal/OSHA requirements for worker protection:

  • PPE (Personal Protective Equipment): hard hat, safety glasses, gloves, steel-toed boots required on most job sites
  • Respiratory protection: required when working with solvents (PVC primer/cement), soldering flux, or lead — Cal/OSHA § 5144
  • Hearing protection: required at or above 85 dB TWA (8-hour time-weighted average)
  • Fall protection: required for work 6 ft or more above ground on construction sites; 4 ft in general industry
  • Ladder safety: 3-point contact rule; extension ladders must extend 3 ft above the landing; angle = 4:1 ratio

Cal/OSHA Title 8 § 3380 — PPE requirements.

🏗 Job Site Safety

  • Confined spaces: any space with limited entry/exit and not designed for continuous occupancy (manholes, crawlspaces under 24"). Requires permit if atmospheric hazards exist. Cal/OSHA § 5157
  • Lockout/Tagout (LOTO): required before servicing any equipment that could unexpectedly energize. Isolate energy source, apply lock, and verify zero energy. Cal/OSHA § 3314
  • Fire watch: required when using torch or open flame within 35 ft of combustibles; maintain for 30 minutes after work stops
  • Soldering/brazing: lead-free solder (95/5 tin-antimony or similar) required for potable water systems since 1988 (federal Safe Drinking Water Act)
  • Right-to-Know / Hazard Communication: Safety Data Sheets (SDS) must be on site for all hazardous chemicals. Cal/OSHA § 5194
  • Traffic control: work in public ROW requires traffic control per CA MUTCD; use flaggers, cones, and signs

🌿 Environmental Safety

  • Stormwater: no plumbing materials or waste may enter storm drains; NPDES permit may be required for larger sites
  • Backflow prevention protects public water supply — cross-connection between potable and non-potable systems is a major environmental violation
  • Chemical spills: contain immediately; report to CalOES (911) if quantity exceeds reportable threshold
  • Asbestos: stop work and notify AHJ if discovered unexpectedly; requires licensed abatement contractor
  • Lead service lines: replacement required in many jurisdictions; consult local water authority
Confined Space Classification:
• Non-permit: large enough to enter, limited egress, not designed for continuous occupancy
• Permit-required: above PLUS one of: hazardous atmosphere, engulfment risk, internal configuration hazard, or other recognized serious safety hazard
Never enter a permit-required confined space without a written permit, trained attendant, retrieval equipment, and atmospheric testing. This is a life-safety requirement — and a tested exam topic.

🔥 Torch Safety & Soldering

  • Use lead-free solder on all potable water systems (tin-antimony, tin-silver, or equivalent)
  • Wrap flammable material with a fire-retardant shield (soldering pad) when working near framing
  • Ensure fire extinguisher (Class B for solvent fires, Class ABC for general) is within reach
  • Propane torches: never use in confined space without ventilation — asphyxiation risk from CO

Cal/OSHA § 8395 — Welding and cutting safety requirements.

Lead-free solder melts at a higher temperature than lead solder. Use a proper flux and more heat — but don't overheat copper; it will oxidize and the solder won't flow correctly.
Practice Quiz

Real-style questions matching actual CSLB exam format — 4 choices, one best answer. Explanations with code references after each answer.

Section: All
Question: 1 / 25
Score: 0 correct
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Flashcards

Click the card to flip and reveal the answer. Use the arrows to move between cards. Great for memorizing code numbers, fixture units, and key rules.

QUESTION — Click to flip
ANSWER
1 / 30

📋 All Flashcards at a Glance

Quick-reference list — all terms and answers:

Math & Formulas

Interactive calculators for the most common plumbing math problems on the C-36 exam. All formulas shown with step-by-step work.

📐 Drain Slope Calculator

Formula: Drop = Length × Slope — Pipes 3" and under: use ¼"/ft slope. Pipes 4" and over: use ⅛"/ft slope.

Enter values above to calculate drop

💰 Job Cost Estimator

Formula: Total = Materials + (Hours × Rate) + (Days × Equipment Rate)

Enter values to calculate total job cost

🚽 DFU (Drainage Fixture Unit) Counter

CPC Table 7-3 — Total DFU determines minimum drain pipe size.

Enter fixture counts above
Minimum Drain Pipe Size by DFU (CPC Table 7-5):
≤1 DFU → 1¼"  |  ≤3 DFU → 1½"  |  ≤6 DFU → 2"  |  ≤12 DFU → 2½"  |  ≤20 DFU → 3"  |  ≤160 DFU → 4"  |  ≤360 DFU → 6"

📊 Essential Formula Sheet

DRAIN SLOPE:
Drop (in) = Length (ft) × Slope (in/ft)
Standard: ¼"/ft for ≤3" pipe
Standard: ⅛"/ft for ≥4" pipe
WATER HAMMER ARRESTOR SIZING:
Based on WSFU demand at fixture group
Refer to PDI Standard WH-201 Table
PRESSURE LOSS IN PIPE:
Use Hazen-Williams or friction loss tables
For exam: know that longer pipe = more loss
Smaller pipe diameter = more friction loss
JOB COST:
Total = Mat + Labor + Equipment + Overhead
Labor = Hours × Hourly Rate
Equipment = Days × Daily Rate
Overhead = (Mat + Labor + Equip) × %
VOLUME OF PIPE (gallons):
V = π × r² × L ÷ 231
(r in inches, L in inches)
Or use: 1" pipe ≈ 0.04 gal/ft
2" pipe ≈ 0.16 gal/ft
4" pipe ≈ 0.65 gal/ft
FLOW RATE (GPM):
GPM = Volume (gal) ÷ Time (min)
For grease interceptors:
GPM = Fixture Cap (gal) ÷ Drain Time (min) × Factor
Quick Code Reference

Key code sections, fixture values, and sizing tables. Memorize these — you can't bring books into the exam.

FixtureDFU (Private)DFU (Public)Trap SizeCPC Reference
Lavatory (sink)121¼"Table 7-3
Bathtub221½"Table 7-3
Shower (single head)222"Table 7-3
Water Closet (toilet)463" (integral)Table 7-3
Kitchen Sink (residential)241½"Table 7-3
Dishwasher22via sinkTable 7-3
Washing Machine222"Table 7-3
Floor Drain222"Table 7-3
Urinal (wall hung)442"Table 7-3
Slop Sink / Mop Sink333"Table 7-3
Total DFUMin Drain Pipe DiameterNotes
1 DFU1¼"Lavatory only
Up to 3 DFU1½"Small branch
Up to 6 DFU2"Common branch
Up to 12 DFU2½"Larger branch
Up to 20 DFU3"Stack or branch
Up to 160 DFU4"Building drain / sewer
Up to 360 DFU6"Large commercial
Up to 620 DFU8"Very large commercial
Code / StandardTopic CoveredExam Relevance
2022 CPC Chapter 4Fixtures & fittingsHigh — finish plumbing
2022 CPC Chapter 6Water supply, backflow preventionHigh — cross-connection
2022 CPC Chapter 7Drainage systems, DFU sizingVery High — math questions
2022 CPC Chapter 9Venting systemsVery High — vent sizing
2022 CPC Chapter 12Fuel gas pipingHigh — gas test pressures
2022 CPC § 501–508Water heaters, T&P valveHigh — safety questions
CALGreen § 4.303Water conservation / flow ratesMedium — GPM/GPF limits
Cal/OSHA Title 8 § 1541Excavation & trenchingHigh — safety section
Cal/OSHA Title 8 § 5157Confined spacesHigh — safety section
Cal/OSHA Title 8 § 3314Lockout/TagoutMedium
CA Govt Code § 4216Underground Dig Alert / 811High — excavation
CA B&P Code § 7028Unlicensed contracting violationMedium — Law & Business
Test TypePressureDurationCode
DWV — Water TestFill to highest point15 minutesCPC § 723.0
DWV — Air Test5 psi (max 6 psi)15 minutesCPC § 723.0
Water Supply100 psi or 1.5× working pressure15 minutesCPC § 609.4
Gas Piping1.5× working or 3 psi min10 minutesCPC § 1215
Shower PanWater fill (2" above threshold)24 hoursCPC § 408.8
Your Road to Passing

A structured 10-week plan designed around the exam's section weights. Follow this plan to be fully prepared by exam day. Adjust the pace if you have 2 months — compress Weeks 1–8 slightly.

📊 Weekly Study Time Recommendation

Minimum: 8–10 hours/week (1.5 hr weekdays + 2 hrs each weekend day)
Optimal: 12–15 hours/week (2 hrs weekdays + 3 hrs each weekend day)
Goal: Score 80%+ on practice quizzes before test day (passing is 70%)
WEEKS 1–2
📐 Section 1: Planning & Estimating + Exam Orientation
Goals: Understand the exam format. Master pipe sizing (DFU), venting rules, and cost estimation formulas.

Daily tasks: Read CPC Chapter 7 (drainage) and Chapter 9 (venting). Work through all Planning & Estimating study notes above. Do the DFU calculator until you can size a 3-bathroom house from memory. Practice 20 math problems per day.

Quiz target: Score 70%+ on Planning section quizzes before moving on.

Flashcards: All DFU values, trap sizes, vent distances. Drill until automatic.
WEEKS 3–4
⛏ Section 2: Underground & Rough Systems
Goals: Master excavation safety (soil types, shoring), underground pipe installation, slope calculations, fuel gas testing, and system pressure tests.

Daily tasks: Study Cal/OSHA Title 8 § 1541 (excavations). Memorize trench sloping angles for soil types A, B, C. Practice slope calculations (Drop = Length × Slope). Review gas piping materials (CSST bonding requirement).

Quiz target: Score 70%+ on Underground section. Focus on test pressures and durations — these are guaranteed exam questions.

Flashcards: Test pressures, soil type angles, 811 call requirements, pipe bedding rules.
WEEKS 5–6
🚿 Sections 3 & 4: Finish Plumbing + Service & Repair
Goals: Know water heater code cold (seismic strapping, T&P valve, expansion tank). Know all backflow device types. Be able to diagnose plumbing problems and choose the right pipe repair method.

Daily tasks: Study CPC § 501–508 (water heaters). Review all backflow preventer types and when each is required. Study repair methods by pipe material. Practice troubleshooting scenario questions.

Quiz target: Score 75%+ on combined Finish + Service sections.

Flashcards: Water heater code points, backflow types (AVB, PVB, DCVA, RPZ), pipe joining methods by material.
WEEK 7
🦺 Section 5: Safety + Water Conservation
Goals: Master confined space rules (permit vs. non-permit), fall protection heights, LOTO procedure, PPE requirements, and CALGreen flow rate limits.

Daily tasks: Study Cal/OSHA § 5157 (confined spaces). Memorize CALGreen flow rates (showerhead: 1.8 GPM, WC: 1.28 GPF, etc.). Study disposal rules for lead, asbestos, refrigerants. Practice safety scenario questions — they are straightforward if you know the rules.

Quiz target: Score 80%+ on Safety section — it's the most formula-free and should be your highest-scoring section.
WEEKS 8–9
🧠 Full Practice Exams + Weak Area Review
Goals: Simulate real exam conditions. Identify weak areas and drill them.

Daily tasks: Take one full 25-question mixed quiz per day under timed conditions (no notes). Review every wrong answer — understand WHY it's wrong, not just what the right answer is. Spend extra time on any section where you score below 70%. Go back through flashcards daily.

Target: Score 80%+ consistently on mixed quizzes before exam day. If you're hitting 75–80%, you're on track.
WEEK 10 — EXAM WEEK
✅ Final Review + Exam Day
Monday–Wednesday: Light review only — go through all flashcards once, review your formula sheet, and do one short 15-question quiz per day. No heavy cramming.

Thursday: Rest day. Light walk through code reference tables. Good sleep is more valuable than 2 more hours of study.

Exam Day: Arrive early. Bring government-issued photo ID. The calculator is provided. Read each question fully — CSLB tests for the BEST answer, and distractor options are designed to trick you if you read too fast. Flag and skip hard questions; come back at the end. No penalty for guessing — fill in every answer.

Trust your preparation. If you followed this plan, you're ready. Most questions will feel familiar. The ones that don't — use the process of elimination to get to 2 choices, then pick the safer/more conservative code answer.

📌 What Else You'll Need

Two Exams Required

To get your C-36 license you must pass TWO exams:
1. The C-36 Trade Exam (this course covers this)
2. The Law & Business Exam (general contractor laws, CSLB regulations, business practices)

Study the Law & Business exam separately — it covers contracting laws, lien rights, insurance, workers' comp, and CSLB regulations.

Requirements Checklist

  • ☐ 4 years plumbing experience (last 10 years)
  • ☐ Application Form 13A-1 submitted to CSLB
  • ☐ $450 application fee paid
  • ☐ $15,000 contractor bond on file
  • ☐ Workers' comp insurance (if you have employees)
  • ☐ Pass Trade Exam (this course)
  • ☐ Pass Law & Business Exam
  • ☐ Receive C-36 license from CSLB