Exam Cheat Sheet · Quick Reference

South Carolina Plumber

South Carolina  ·  PSI Services Contractor

Verified, not estimated. Every figure below is drawn from the official exam structure we maintain — question counts, passing standard and topic weighting. Practice questions are grounded in the source law with statute citations. We omit any figure we can't verify rather than guess at it.
Total questions
80
Passing score
70%
Exam time
240 min
Administered by
PSI Services Contractor
Format
Reference materials allowed

South Carolina State Portion 80 questions

ADA Accessibility 1 Q · 1%
Water closet location, clearance dimensions, and seat height requirementsGrab bar specifications for toilet and bathing facilities (dimensions, placement, structural strength)Accessible and ambulatory toilet compartment size and door requirementsDrinking fountain requirements for wheelchair users and standing persons (spout height, location, water flow)Shower compartment types and dimensions (transfer-type, standard roll-in, alternate roll-in)Lavatory and sink clearances, mounting heights, and knee/toe clearanceAccessible bathtub requirements (clearances, grab bars, controls, hand shower, seat dimensions)Turning space and clear floor space dimensions for accessible toilet and bathing rooms
General Plumbing Knowledge 6 Q · 8%
IPC code scope, purpose, and applicability to plumbing systemsPermits: application, issuance, expiration, and exempt workInspections and testing requirements (underground, rough-in, final, and system pressure tests)Code official authority, duties, violations, and stop work ordersKey plumbing terminology and definitions (IPC Chapter 2)General installation regulations: pipe protection, support intervals, trenching, and backfillSC 811 one-call notification requirements, excavator responsibilities, and tolerance zone rulesBasic plumbing mathematics: measurements, formulas, geometry, and unit conversions
General Plumbing Regulations 3 Q · 4%
Permit application, issuance, expiration, and exemptionsCode official authority, duties, and enforcement powersInspections and testing requirements for plumbing systemsViolations, stop work orders, and unsafe plumbing condemnationSC 811 excavator notification requirements and locate request proceduresTolerance zone requirements and hand-dig rules near underground facilitiesEmergency excavation procedures and damage reporting under SC lawPlumbing business licensing, bonding, and contractor responsibilities
Hangers and Supports (General) 2 Q · 2%
Hanger spacing intervals by pipe material (Table 308.5)Maximum horizontal and vertical support spacing requirementsApproved materials for hangers, anchors, and supports (galvanic action prevention)Structural attachment of hangers and anchors to building constructionSway bracing for horizontal drainage pipes at direction changesAnchorage and restraint of drainage piping at direction and diameter changesSupport requirements for thermal expansion tanks and manifold piping systemsDefinition and equivalence of hangers, anchors, and supports terms
Materials 2 Q · 2%
Approved pipe and fitting standards for water service and distribution systems (Table 605.3, 605.4, 605.5)Approved pipe and fitting standards for sanitary drainage, waste, and vent systems (Tables 702.1, 702.2, 702.3, 702.4)Joining methods and joint types by pipe material (solvent cement, solder, braze, heat fusion, mechanical, press-connect, push-fit)Prohibited joints and connections for water supply and drainage pipingGas piping materials — metallic pipe, tubing, CSST, and plastic pipe standards (IFGC Section 403)Lead content restrictions for water supply pipe, fittings, valves, and solderMaterial identification, third-party certification, and manufacturer markings requirementsApproved materials for vent pipe flashings and specialty fixture construction
Joints and Connections 3 Q · 4%
Joint types by pipe material (ABS, PVC, CPVC, PEX, copper, steel, cast iron)Prohibited joints and connections in water supply and sanitary drainage systemsSolvent cementing procedures and primer requirements for plastic pipeSolder and brazed joint requirements for copper pipe and tubingMechanical and press-connect joint installation requirementsJoints between dissimilar piping materials and dielectric fittingsGas piping joint and fitting requirements (threaded, brazed, welded, flared)Fitting allowances and pipe length calculations for threaded, copper, and plastic fittings
Fixtures and Equipment 3 Q · 4%
Minimum number of plumbing fixtures by occupancy typeFixture installation requirements and clearancesFixture materials and product standardsWater heater safety devices and relief valvesWater heater installation, access, and location requirementsAccessible plumbing fixtures and facilities (ICC A117.1)Faucets, shower valves, and temperature-limiting devicesGas-fired appliances and specific equipment requirements
Water Heaters 4 Q · 5%
Temperature and pressure relief valve requirements and discharge pipingSafety devices (antisiphon devices, vacuum relief valves, pan requirements)Water heater installation requirements (location, access, clearances, attic installations)Cold water supply valve and connection requirementsTemperature controls and maximum water temperature limitsGas-fired water heater listing and installation standards (ANSI Z21.10.1/CSA 4.1, IFGC compliance)Water heaters used for space heating (combination systems, mixing valve requirements)Unfired hot water storage tank insulation requirements
Water Supply and Distribution 3 Q · 4%
Backflow prevention devices and assemblies (air gaps, vacuum breakers, reduced pressure principle, double check assemblies)Cross-connection control and potable water system protectionWater service pipe materials, standards, and installation requirementsWater distribution pipe materials, fittings, joints, and connection methodsPipe sizing using water supply fixture units and pressure loss calculationsPressure regulation, water hammer arrestors, and booster systemsHot water supply system requirements including temperature limits, recirculation, and thermal expansion controlWater heater installation, safety devices, and relief valve discharge piping
Backflow Prevention 1 Q · 1%
Types of backflow (backsiphonage vs. backpressure) and hazard levels (high vs. low hazard contamination vs. pollution)Reduced pressure principle backflow prevention assemblies — application and installation requirementsVacuum breakers — atmospheric-type, pressure vacuum breaker, and spill-resistant types — installation height and use limitationsDouble check backflow prevention assemblies — application to low-hazard and fire protection systemsAir gap requirements — minimum dimensions and application per Table 608.16.1Backflow preventer device selection per Table 608.1 — matching device to degree of hazard and backflow typeSpecial connections requiring backflow protection — boilers, irrigation systems, sprinkler systems, carbonated beverage dispensers, and chemical dispensersBackflow preventer location, access, freeze protection, and relief port discharge requirements
Sanitary Drainage Systems 4 Q · 5%
Drainage fixture unit (DFU) values and system sizing tablesHorizontal drainage pipe slope requirementsCleanout placement, sizing, and access requirementsPipe materials and joint types for above-ground, underground, and building sewer applicationsSumps, ejectors, and below-grade drainage systemsTrap requirements, prohibited trap types, and trap seal protectionGrease interceptors, oil separators, and other interceptor/separator requirementsIndirect waste piping, air gaps, air breaks, and waste receptors
Cleanouts 2 Q · 2%
Required locations for cleanouts (horizontal drains, building drains, building sewers, and direction changes)Cleanout spacing intervals and measurement methodsCleanout sizing requirements relative to pipe size servedCleanout plug materials and head typesClearance requirements for cleanout accessCleanout installation arrangement and direction of cleaningCleanout equivalents (fixture traps, removable P-traps)Prohibited use of cleanout openings for fixture or piping extensions
Indirect and Special Waste 2 Q · 2%
Air gap vs. air break requirements and distinctionsWhere indirect waste connections are required (food handling, dishwashers, pools, sterilizers, humidifiers)Waste receptor types, installation requirements, and prohibited locationsIndirect waste pipe trapping requirements and length limitsStandpipe installation requirements and dimensional limitsNeutralizing and dilution devices for corrosive/chemical wastesSeparation of chemical drainage and vent systems from sanitary systems
Sanitary Venting 6 Q · 8%
Trap seal protection and maximum allowable pressure differentialVent terminal requirements and prohibited locationsVent pipe sizing using drainage fixture units and developed lengthTypes of venting methods: individual, common, wet, circuit, combination waste and vent, and waste stack ventAir admittance valves: installation, location, size, and use limitationsVent connections, grading, and vertical rise requirementsRelief vents for stacks exceeding 10 branch intervalsFrost closure and outdoor vent extension requirements
Traps and Interceptors 3 Q · 4%
Fixture trap requirements (distance limits, sizing, and prohibited trap types)Trap seal depth requirements and protection methods (primer valves, barrier devices, fixture drain connections)Grease interceptors and automatic grease removal devices (where required, sizing, and installation)Oil separators (required locations, design standards, and capacity requirements)Sand, solids, and specialty interceptors (clothes washers, bottling plants, slaughterhouses)Venting of interceptors and separators to prevent air bindingAccess and maintenance requirements for interceptors and separatorsMaterials, joints, and connections for traps, interceptors, and separators
Storm Piping Systems 2 Q · 2%
Storm drain pipe sizing using rainfall rate and roof area calculations (GPM formula)Acceptable piping materials and standards for storm drainage conductors, building storm drains, and building storm sewersRoof drain requirements, flow rates, and installation standardsSecondary (emergency) roof drains and scuppers: sizing, placement, and discharge requirementsSubsoil drain systems: pipe types, minimum diameter, backwater protection, and discharge locationsSump pits and pumping systems: pit dimensions, pump capacity, discharge piping, and valve requirementsSiphonic and controlled flow roof drain system requirements100-year hourly rainfall rates for South Carolina cities and application to storm system design
Plumbing - Developed Length 5 Q · 6%
Center-to-center vs. end-to-end pipe length calculationsFitting allowances for threaded, copper, PVC, and cast iron fittingsOffset, diagonal, rise, and run calculations using angle constants (45°, 60°, 22½°, 11¼°)Rolling offsets and true offset calculationsGrade, drop, and slope of horizontal drainage pipingDeveloped length measurement for cleanout spacing requirements (IPC Section 708)Developed length of hot water piping from source to fixture (IPC Section 607.2)Equivalent length of fittings and valves for water piping system sizing
DWV Isometric Analysis (Isometric Based) 10 Q · 12%
Fixture unit (DFU) values and drainage load calculations from isometric drawingsHorizontal and vertical drain pipe sizing using Tables 710.1(1) and 710.1(2)Pipe slope requirements for horizontal drainage pipingVent pipe sizing and developed length determination from isometric layoutsTrap-to-vent distance limits and fixture drain slope requirementsOffset pipe length calculations using 45° constants (diagonal, rise, run)Cleanout placement requirements identifiable from isometric diagramsTrap seal requirements and prohibited trap types identifiable in system layouts
Water Supply Isometric Analysis 4 Q · 5%
Water supply fixture units (WSFU) and peak demand estimationPressure loss calculations: elevation head, meter loss, tap loss, and friction lossSegmented loss method for sizing water service and distribution pipingEquivalent length of fittings and valves in pipe sizing calculationsPipe offset geometry: diagonal, rise, run, and angle constants for isometric layoutFitting allowances and end-to-end pipe length calculations for threaded, copper, and plastic pipeMinimum fixture supply pipe sizes and flow pressure requirements per IPC Table 604.3 and 604.5Water pressure requirements, pressure-reducing valves, and booster systems
Roof Drain Isometric Analysis 3 Q · 4%
Rainfall rate conversion to GPM using IPC Equation 11-1Roof drain flow rate and head-based sizing requirementsHorizontal and vertical storm drain pipe sizing using IPC Table 1106.2Vertical leader sizing using IPC Table 1106.3Secondary (emergency) roof drain and scupper sizing requirements100-year hourly rainfall rates for specific cities and geographic regionsIsometric pipe length calculations using center-to-center and end-to-end methods with offset constantsMinimum roof drain quantity requirements and controlled flow system rules
Pipe Assembly 1 Q · 1%
Fitting allowance calculations for threaded, copper, PVC, and welded pipeCenter-to-center and end-to-end pipe length measurementsPipe offset geometry using 45° and other angle constantsJoint types and connection methods by pipe materialPipe material types, weights, and schedulesDrainage piping slope and change-of-direction fitting requirementsPipe support intervals and protection requirementsGas piping materials, joint types, and installation requirements
Valves 1 Q · 1%
Full-open valve and shutoff valve placement requirements (IPC 606.1–606.2)Water pressure-reducing valves (ASSE 1003) and pressure booster systemsTemperature and pressure relief valves for water heaters (ANSI Z21.22, IPC 504)Backflow preventer valve types, hazard classification, and applicable standards (IPC Table 608.1)Gas shutoff valve location, access, and identification requirements (IFGC 409)Gas appliance shutoff valve standards and placement (IFGC Table 409.1.1)Backwater valves for sanitary drainage systems (IPC 714)Valve compatibility with piping materials and lead-content requirements (IPC 605.7)
General Fuel Knowledge 3 Q · 4%
Fuel gas types and properties (natural gas, LP-gas, manufactured gas, specific gravity, BTU content)Key IFGC definitions and terminology for fuel gas systemsIFGC scope and applicability of fuel gas code regulationsProhibited and approved appliance locations and installation requirementsCombustion air requirements and calculation methodsGas leak recognition (smell, sight, sound indicators)Appliance listing, labeling, and approval requirementsElectrical bonding and grounding requirements for gas piping systems
Natural Gas 3 Q · 4%
Gas piping materials, fittings, and approved standards (steel, copper, CSST, polyethylene)Pipe sizing methods and capacity tables (longest length, branch length, hybrid pressure methods)Allowable pressure drop and maximum operating pressure inside buildingsCombustion air requirements for gas appliances (indoor, outdoor, and combination methods)Venting systems for gas appliances (Type B, single-wall, chimneys, vent connectors, termination clearances)Gas piping installation requirements (support, identification, testing, purging, leak checks)Appliance location, clearances, and prohibited installation areasGas leak recognition and emergency response procedures
LP - Gas 3 Q · 4%
LP-gas piping system design and sizing methods (longest length, branch length, hybrid pressure)Allowable piping materials and fittings for LP-gas systems (metallic pipe, copper tubing, CSST, polyethylene plastic)LP-gas operating pressure requirements and maximum pressure limits (first-stage, second-stage, low-pressure regulators)LP-gas storage system requirements and compliance with NFPA 58Pressure testing and leak checking of LP-gas piping systemsVenting requirements for LP-gas appliances (vent types, termination, sizing)Combustion air requirements for LP-gas appliancesLP-gas system operation below -5°F and prevention of liquid condensation

Key Distinctions

Flow pressurevsStatic pressure

Flow pressure is the pressure in the supply pipe near the faucet/outlet while it is wide open and flowing, while static pressure is the no-flow pressure due to elevation head (0.433 psi per foot of vertical height).

IPC 2021 Page 2-4
Copper (solder) fitting allowancevsThreaded fitting allowance

Copper allowance equals center-to-face minus the depth of the solder cup with no thread-in deduction, whereas threaded fittings require a thread-in deduction.

Mathematics for Plumbers, Unit 10, Pages 56-57 (Allowances for Copper Fittings)
PVC (plastic) fitting allowancevsThreaded fitting allowance

PVC allowance is measured from center to the outside shoulder of the hub cup using the same steps as copper fittings; unlike threaded fittings, PVC requires no thread-in deduction step.

Mathematics for Plumbers, Unit 12, Pages 60-61 (Allowance for Plastic Fittings)
Type B-W gas vent terminationvsType B or L gas vent termination

A Type B-W vent must terminate not less than 12 feet in vertical height above the bottom of the wall furnace, while Type B or L vents must terminate not less than 5 feet above the highest connected appliance draft hood or flue collar.

SC Fuel Gas Code 2021, Chapter 5 Chimneys and Vents, Section 503.6.6
Short sweep (or long sweep)vsSanitary tee

A short or long sweep is permitted for horizontal-to-horizontal changes of direction, while a sanitary tee is permitted only for horizontal-to-vertical connections.

IPC 2021 Table 706.3
Horizontal stack offset sizingvsVertical stack sizing

Horizontal stack offsets are sized as required for building drains per Table 710.1(1) rather than by the stack sizing table.

IPC 2021 Section 710.1.1
Copper tubing Types K and LvsCopper tubing Types M and DWV

For building sewer pipe, copper/copper-alloy tubing is limited to Type K or L; Types M and DWV are not permitted.

IPC 2021 Table 702.3
Above-ground drainage and vent materials (Table 702.1)vsUnderground drainage and vent materials (Table 702.2)

Polyethylene (PE) plastic pipe (SDR-PR) is listed only for underground building drainage and vent piping, while cast iron, ABS, and copper tubing appear in both tables.

IPC 2021 Tables 702.1 and 702.2
CPVC solvent cement (two-step with primer)vsCPVC one-step solvent cement

Where a primer is required the cement must be orange in color conforming to ASTM F493; where a one-step cement is allowed it must be yellow in color conforming to ASTM F493.

IPC 2021 Section 605.14.2
PVC solvent-cemented water supply jointsvsCPVC solvent-cemented water supply joints

PVC requires purple primer conforming to ASTM F656 with cement conforming to ASTM D2564, while CPVC two-step joints use an approved primer with orange cement conforming to ASTM F493.

IRC Section P2906.9.1.4
Wet ventvsCircuit vent / combination waste-and-vent

A wet vent vents one or more fixtures while also carrying the discharge of another fixture (classically a single bathroom group), whereas circuit vents serve batteries of fixtures and combination waste-and-vent is a different, more restricted system.

Full-open valvevsFixture shutoff (stop) valve

Section 606.1 requires full-open valves at locations such as the water service entrance, riser base, and the supply pipe to every water heater, while Section 606.2 requires a shutoff (stop) valve on each fixture supply.

IPC 2021 Section 606.1
Elevations on sewers and house drainsvsElevations on most other pipe

Sewers and house drains are measured to the invert (inside bottom) of the pipe, while most pipes are measured to the centerline.

Mathematics for Plumbers and Pipefitters (8th ed.), Page 129 (Unit 34)

Key Terms

Flow pressure IPC 2021 Page 2-4
The pressure in the water supply pipe near the faucet or water outlet while that faucet or outlet is wide open and flowing.
Faucet IPC 2021 Page 2-4
A valve end of a water pipe through which water is drawn from or held within the pipe.
Effective opening IPC 2021 Page 2-3
The minimum cross-sectional area at the point of water supply discharge expressed as the diameter of a circle (or equivalent-area circle if not round); for faucets and similar fittings it is measured at the smallest orifice in the fitting body or supply piping to the fitting.
Developed length IPC 2021 Page 2-3
The length of a pipeline measured along the centerline of the pipe and fittings.
Branch interval IPC 2021 Definitions (Branch Interval)
A vertical measurement of distance of 8 feet or more in developed length between the connections of horizontal branches to a drainage stack.
Building drain IPC 2021 Definitions (Building Drain)
The lowest piping that collects discharge from all other drainage piping inside the house and extends 30 inches in developed length beyond the exterior walls to convey drainage to the building sewer.
Backsiphonage IPC 2021 Section 202 Definitions
The backflow of potentially contaminated water into the potable water system because pressure in the potable system falls below atmospheric pressure of the fixtures, pools, tanks or vats connected to the distribution piping.
Cross connection IPC 2021 Section 202 Definitions
Any physical connection or arrangement between two otherwise separate piping systems, one containing potable water and the other water of unknown or questionable safety or steam, gas or chemical, whereby flow from one to the other is possible.
Vent stack IPC 2021 Section 202
A separate vertical vent pipe installed to circulate air through the drainage system, connecting near the base of the soil stack and rejoining the stack vent above the highest fixture.
Vent stack connection to building drain IPC 2021 Section 904.4
Where a vent stack connects to the building drain instead of the drainage stack, the connection must be downstream of the drainage stack and within 10 times the diameter of the drainage stack.
Area drain IPC 2021 Chapter 11
A drain in a paved court or yard that collects surface storm water.
Invert Mathematics for Plumbers and Pipefitters (8th ed.), Page 129 (Unit 34)
The inside bottom of the pipe, used as the reference point for sewer and house drain elevations.
Lead-free solder IPC 2021 Section 605.12.3
Solder and flux for joining water supply piping having a chemical composition equal to or less than 0.2-percent lead.
Water-hammer arrestor IPC 2021 Section 604.9
A device required where quick-closing valves are used; it must conform to ASSE 1010 and be installed per the manufacturer's instructions.
Prohibited joints (water supply) IPC 2021 Section 605.9
Cement or concrete joints, joints made with fittings not approved for the installation, solvent-cement joints between different types of plastic pipe, and saddle-type fittings.
Crown vent prohibition IPC 2021 Section 909.3
A vent shall not be installed within two pipe diameters of the trap weir (e.g., 3 in. for a 1-1/2 in. trap, 4 in. for a 2 in. trap).
Cleanout requirements IPC 2021 Section 708.1.1
Horizontal drainage pipes in buildings need cleanouts at intervals of not more than 100 feet, and a cleanout is required where a horizontal drain, building drain or building sewer changes horizontal direction more than 45 degrees.
Individual vent minimum size rule IPC 2021 Section 906.2
An individual vent is not less than one-half the diameter of the fixture drain it serves but never smaller than 1-1/4 inch, and a vent exceeding 40 feet in developed length is increased one nominal size for its entire length.

Formulas to Know

Static (head) pressure and pressure difference between two pointsStatic psi = vertical height of water above the point (ft) × 0.433 psi/ft; between two fixtures use only the elevation difference (e.g., 38 ft − 6 ft = 32 ft × 0.433 = 13.9 psi); height required = psi ÷ 0.433 (e.g., 30 ÷ 0.433 = 69.3 ft)
Total fall (drop) of a graded horizontal drainFall = grade (in./ft) × run (ft); e.g., 1/8 in/ft × 32 ft = 4 in; 1/4 in/ft × 48 ft = 12 in = 1.00 ft (12 in = 1 ft)
Downstream invert elevationDownstream invert = upstream invert − total fall; e.g., 100.00' − 1.00' = 99.00'; or 101.00 − (8 in + 3 in = 11 in = 0.92 ft) = 100.08 ft
Grade expressed as percent slope% slope = (rise in inches per foot ÷ 12 in) × 100; e.g., (0.25 ÷ 12) × 100 = 2.08%
Cylindrical tank volume and gallon capacityV = π × r² × h (r = diameter ÷ 2); gallons = cubic feet × 7.48; e.g., π × 2² × 6 = 75.4 cu ft × 7.48 = 565 gal (half height uses h ÷ 2)
Water contained in a length of pipeArea = π × r² (r in feet); volume = area × length; gallons = cubic feet × 7.48; e.g., π × (1/12)² = 0.0218 sq ft × 100 ft = 2.18 cu ft × 7.48 = 16.3 gal
Water heater recovery rate (gallons per hour)GPH = (input BTU/hr × efficiency) ÷ (8.33 lb/gal × temperature rise °F); e.g., (40,000 × 0.75) ÷ (8.33 × 70) = 30,000 ÷ 583.1 = 51.4 GPH
Maximum allowable friction loss rate for pipe sizingAllowable rate = (available pressure ÷ total equivalent length) × 100; e.g., (22 psi ÷ 250 ft) × 100 = 8.8 psi per 100 ft
Equivalent length allowances for fittings and valvesSegmented loss method: add 50% of developed length (developed length × 1.5), e.g., 225 ft × 1.5 = 338 ft; Section E104.1 method: maximum developed length to the most remote fixture × 1.2
Rolling offset true offset and travel; pipe cut lengthTrue offset = √(set² + roll²), e.g., √(12² + 9²) = 15.0 in; travel = true offset × 1.414 for 45° or × 1.155 for 60°; cut length = center-to-center − (fitting allowance per end × 2), e.g., 24 − (2 × 1/2) = 23.00 in
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