Exam Cheat Sheet · Quick Reference
Maryland Journeyman Plumber / Gas Fitter
Maryland · 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
100
Passing score
70%
Exam time
240 min
Administered by
PSI Services Contractor
Format
Reference materials allowed
Maryland State Portion 100 questions
Plumbing Fundamentals and Safety
8 Q · 8%
IPC code scope, intent, and applicability to plumbing systemsPermit requirements, applications, and exemptions for plumbing workCode official authority, duties, inspections, and enforcementKey plumbing terminology and definitions (IPC Chapter 2)Employer accident prevention responsibilities and safety program requirements (OSHA 1926 Subpart C)Personal protective equipment selection, provision, and employer payment obligationsJobsite sanitation requirements including potable water, toilets, and washing facilitiesOccupational health hazards including noise exposure limits, airborne contaminants, and lead exposure controls
Materials, Uses, and Specifications
6 Q · 6%
Approved piping materials and standards for gas piping (metallic pipe, copper tubing, CSST, polyethylene plastic)Prohibited materials and material restrictions (cast iron pipe, aluminum in exterior/underground locations, copper with high hydrogen sulfide content, PVC/CPVC for fuel gas)Fitting types, joint methods, and connection standards (threaded, brazed, welded, press-connect, flared joints)Pipe and tubing identification markings and manufacturer labeling requirementsProtective coatings and corrosion protection for metallic pipingPlastic pipe and tubing specifications and limitations (polyethylene ASTM D2513, polyamide ASTM F2945, underground-only use)Referenced standards for gas piping materials (ASTM, ASME, ANSI/CSA designations)Plumbing pipe and fitting material standards referenced in IPC (copper, steel, plastic, cast iron per ASTM and ASME standards)
Traps, Interceptors, and Backwater Valves
4 Q · 4%
Fixture trap requirements and prohibited trap typesTrap seal depth requirements and protection methodsGrease interceptor requirements and exemptionsGrease interceptor sizing and grease retention capacityOil separator requirements and design specificationsSand, solids, and specialty interceptorsVenting and access requirements for interceptors and separators
Plumbing Fixtures, Fixture Fittings, and Plumbing Appliances
4 Q · 4%
Minimum number of plumbing fixtures by occupancy typeFixture installation requirements (spacing, clearances, and setting)Fixture material standards and product approvalsFlushing devices for water closets and urinals (flushometer valves, flush tanks, fill valves)Shower compartment requirements (dimensions, lining, waste outlets, and valves)Water heater installation (location, access, clearances, drain valves, and pressure marking)Temperature and pressure relief valves for water heaters (installation, discharge piping, and pan requirements)Gas-fired appliance installation requirements (cooking appliances, water heaters, clothes dryers, and specific gas appliances)
Water Supply Systems
8 Q · 8%
Backflow prevention devices and assemblies (air gaps, vacuum breakers, reduced pressure principle, double check)Pipe and fitting materials for water service and distribution (copper, PEX, CPVC, PVC, PE, galvanized steel)Joining methods by pipe material (solvent cement, solder, brazing, mechanical, heat fusion, push-fit)Water pressure requirements, pressure-reducing valves, and booster systemsFixture supply pipe sizing and minimum flow rates/pressures at outletsPotable water protection and cross-connection controlWater volume, weight, and capacity calculations (rectangular, cylindrical, and spherical tanks)Water pressure and head calculations (psi from height, height from psi, force on plugs)
Backflow Prevention
10 Q · 10%
Cross-connection hazard classification (high hazard contamination vs. low hazard pollution)Backflow preventer device types and applicable standards (ASSE 1001, 1011, 1013, 1015, 1020, 1024, etc.)Air gap requirements and minimum air gap dimensions by fixture typeReduced pressure principle backflow prevention assembly installation and relief port dischargeVacuum breaker types, installation height requirements, and critical level specificationsSpecific connection protection requirements (boilers, lawn irrigation, fire sprinkler systems, carbonated beverage dispensers, hose bibbs)Thermal expansion control where backflow preventers are installed on water heater cold water supplyLocation, access, and protection of backflow prevention devices including outdoor enclosures
Drain, Waste, and Vent Systems
13 Q · 13%
Drainage fixture unit (DFU) values and load calculationsSizing of building drains, sewers, and horizontal branchesSlope requirements for horizontal drainage pipingCleanout placement, spacing, size, and access requirementsVent pipe types, sizing, and developed lengthTrap-to-vent distance and fixture vent connectionsIndirect waste piping, air gaps, and air breaksStorm drainage system sizing and roof drain requirements
Gas Appliances and Piping
40 Q · 40%
Gas piping materials, fittings, and installation requirementsGas pipe sizing methods and capacity tablesPressure testing, purging, and leak detection of gas piping systemsCombustion air requirements for gas appliancesVenting systems for gas appliances — types, sizing, and terminationAppliance location, clearances, and prohibited installationsCSST bonding and electrical grounding requirementsSafety inspection procedures for existing gas appliance installations
Plumbing Mathematics
7 Q · 7%
Fraction, decimal, and unit conversion for pipe measurementsFitting allowance calculations for threaded, copper, PVC, and welded pipeOffset, diagonal, rise, and run calculations using angle constantsPipe length calculations for parallel offsets, rolling offsets, and combination offsetsGrade, percent grade, drop, and elevation calculations for drainage pipeVolume, capacity, and water pressure calculations for cylinders and rectangular tanksBasic arithmetic and formula solving with geometric shapesPipe bending calculations including gain, arc length, and bend angle
Key Distinctions
High hazard cross-connection (contamination)vsLow hazard cross-connection (pollution)
High hazard is 'contamination' per Section 202 — substances that could cause illness or death in the potable supply — while low hazard is 'pollution' — substances that are aesthetically objectionable or degrade water quality but do not create a health hazard.
IPC 2018 Table 608.1 footnotesFull-open valve locationsvsShutoff (stop) valve locations
Full-open valves are required at locations such as the water supply pipe to every water heater, the service entrance, and the base of a water riser (Section 606.1), whereas shutoff valves are required on supplies to sillcocks, appliances/mechanical equipment, and individual fixture supplies other than bathtubs and showers in one- and two-family dwellings (Section 606.2).
IPC 2018 Section 606.1(8)Vacuum breaker for hose connections in health care or laboratory areasvsVacuum breaker for a bedpan washer hose
Health care/laboratory hose-connection vacuum breakers must be not less than 6 feet above the floor, while bedpan washer hose vacuum breakers must be not less than 5 feet above the floor.
UPC Section 608.3.1Pressure vacuum breaker assembly (ASSE 1020)vsDouble check, reduced pressure principle, and intermediate-atmospheric-vent assemblies
A pressure vacuum breaker assembly is rated for backsiphonage only, while double check assemblies, reduced pressure principle assemblies, and backflow preventers with intermediate atmospheric vent are rated for both backpressure and backsiphonage.
UPC Table 608.1Dual-check-valve-type backflow preventer (ASSE 1024)vsSpill-resistant vacuum breaker assembly (ASSE 1056)
The dual-check-valve type is rated low hazard only (backpressure and backsiphonage, sizes ½" to 1"), while the spill-resistant vacuum breaker assembly is rated high or low hazard but for backsiphonage-only applications.
UPC Table 608.1 and Section 605.3.1Tee-wye DWV fittingvsStandard tee
A standard tee has three equal allowances, while a tee-wye has two long allowances and one short allowance, with a ¼-inch-per-foot slope built into the branch.
Mathematics for Plumbers and Pipefitters (8th ed.), Unit 23Regular wyevsReducing wye
On a reducing wye the branch size differs from the run size, so a different allowance applies to the branch (the E dimension), using Data 9 for reduced-branch wyes.
Mathematics for Plumbers and Pipefitters (8th ed.), Unit 23Branch Length Method (gas sizing)vsLongest Length Method (gas sizing)
The Branch Length Method uses the longest length only for the initial parts of the system and then sizes each branch by the actual distance from the meter to the most remote outlet in that branch, instead of applying the overall longest length to every section.
IFGC 2018 Appendix A, Section A.3.2Vitrified clay pipe for building sewervsVitrified clay pipe above ground
Vitrified clay (ASTM C4; ASTM C700) is listed in Table 702.3 as approved building sewer pipe but is not listed in Table 702.1, so it is not permitted for above-ground sanitary drainage and vent piping (cast iron, ABS, and PVC appear in both).
IPC 2018 Chapter 7, Tables 702.1 and 702.3Sewage ejector receiving water closet dischargevsOther pumps or ejectors
Pumps/ejectors receiving water closet discharge must handle spherical solids up to and including 2 inches, while other pumps or ejectors need only handle solids up to 3/4 inch.
IPC 2018 Chapter 7, Section 712.4.2Ventilated thimble sized 4 inches larger than the metal pipevsVentilated thimble sized 2 inches larger
For a listed appliance with a draft hood, the thimble must be at least 4 inches larger in diameter than the single-wall metal pipe; the 2-inch allowance applies only where there is a run of not less than 6 feet of metal pipe in the open between the draft hood outlet and the thimble.
IFGC 2018 Section 503.7.7CSST without an arc-resistant jacket or coatingvsOther gas piping
CSST not listed with an arc-resistant jacket/coating must be electrically continuous AND bonded to the electrical service grounding electrode system — a requirement beyond that for other gas piping; no gas piping may be used as a grounding electrode.
IFGC 2018 Section 310.2Cleanouts on building sewers smaller than 8 inchesvsManholes on building sewers 8 inches and larger
Sewers smaller than 8 inches require cleanouts at intervals of not more than 100 feet; sewers 8 inches and larger require a manhole not more than 200 feet from the building drain/building sewer junction and manholes at intervals of not more than 400 feet.
IPC 2018 Chapter 7, Section 708.1.2General code requirementvsSpecific code requirement
Where a general and a specific requirement conflict, the specific requirement governs; where different sections specify different materials or methods, the most restrictive governs.
IPC 2018 Section 102.1Key Terms
Pressure-reducing valve (building water supply) IPC 2018 Section 604.8.1
A valve that must be designed to remain open to permit uninterrupted water flow in case of valve failure.
Water-hammer arrestor UPC Section 604.9
A device conforming to ASSE 1010 that must be installed where quick-closing valves are utilized.
Barometric loop UPC Section 608.14.4
A backflow protection loop that precedes the point of connection and extends vertically 35 feet, usable only as an atmospheric-type or pressure-type vacuum breaker.
Pressure vacuum breaker assembly UPC Section 608.14.5
A backsiphonage-only backflow assembly installed with its critical level not less than 12 inches above all downstream piping and outlets.
Tempered water UPC Section 607.1.2
Water supplied through a water temperature limiting device conforming to ASSE 1070/ASME A112.1070/CSA B125.70 and limited to not greater than 110°F (43°C).
Demand recirculation water system UPC Section 607.2.1.2
A recirculation system whose pump control must limit the temperature of water entering the cold water piping to 104°F (40°C).
Air gap (potable water treatment equipment) UPC Section 608.4
The required discharge method for overflow, relief valve, and waste pipes from pumps, filters, softeners, and tanks handling potable water; gravity tank potable inlets must also terminate with an air gap of not less than 4 inches above the overflow.
Prohibited water supply joints UPC Section 605.9
Cement or concrete joints, joints made with fittings not approved for the specific installation, solvent-cement joints between different types of plastic pipe, and saddle-type fittings.
Nonpotable water piping identification UPC Sections 608.9.2 and 608.9.2.1
Reclaimed, rain, and gray water distribution piping must be purple in color, with warning-word letters not less than 0.5 inch high on outlet signage and identification tape not less than 3 inches wide with white or black lettering on a purple field.
Bundled water distribution piping marking UPC Section 606.7
Each pipe in a bundle must be identified by stenciling or labels showing contents and flow direction at intervals not exceeding 25 feet, with at least one label per pipe in each room, space, or story.
Wet vent
A pipe that vents one or more fixtures while also carrying the discharge of another fixture, classically a single bathroom group.
EHD (Equivalent Hydraulic Diameter) IFGC 2018 Table 402.4(15), Note 2
In CSST sizing tables, a measure of relative hydraulic efficiency between tubing sizes — the greater the EHD value, the greater the gas capacity.
Gas table baseline specific gravity IFGC 2018 Appendix A, Section A.2.2
Low-pressure natural gas capacity tables are based on 0.60 specific gravity gas; when specific gravity differs, a gravity factor multiplier from Table A.2.4 must be applied.
Appliance shutoff valve location (fuel gas) IFGC 2018 Section 409.1.2
Shutoff valves are prohibited in concealed locations and in furnace plenums.
Copper tubing for fuel gas IFGC 2018 Section 403.5.3
Must comply with Standard Type K or L of ASTM B88 or ASTM B280.
Permit expiration / work without permit IPC 2018 Section 106.5.3
A permit becomes null and void if work is not commenced within 180 days of issuance, and commencing work before obtaining a permit adds a penalty of 100 percent of the usual permit fee in addition to the required fee.
Asbestos PEL (construction) 29 CFR 1926, Subpart Z, §1926.1101(c)(1) and (i)(1)
0.1 fiber per cubic centimeter of air as an 8-hour TWA; protective clothing is required above this limit, regulated-area ventilation must move contaminated air away from breathing zones toward a HEPA device, and employee rotation to reduce exposure is prohibited.
Trench means of egress 29 CFR 1926.651(c)(2)
A stairway, ladder, ramp, or other safe means of egress is required in trenches 4 feet or more deep, located so no employee has more than 25 feet of lateral travel to reach it.
Hole cover marking 29 CFR 1926, Subpart M, §1926.502(i)(4)
Covers over holes in walking/working surfaces must be color coded or marked with the word 'HOLE' or 'COVER'.
Formulas to Know
Static (gauge) pressure from water height
Static pressure (psi) = vertical height of water above the point (ft) × 0.433 psi/ft (e.g., 46 ft × 0.433 = 19.9 ≈ 20 psi; 60 × 0.433 = 26 psi)Water column height needed for a given pressure
Height (ft) = pressure (psi) ÷ 0.433 psi/ft (e.g., 20 ÷ 0.433 = 46.2 ft; 30 ÷ 0.433 = 69.3 ft)Offset travel and run from set using fitting constants
Travel = set × constant: 45° = 1.414, 22½° = 2.613, 60° = 1.155; for a 45° offset run = set × 1.000 (run equals set)Rolling offset true offset, then travel
True offset = √(set² + roll²); then travel = true offset × angle constant (e.g., √(12² + 9²) = 15 in; 15 × 1.414 = 21.2 in; 15 × 1.155 = 17.3 in)Total fall of a graded drain and downstream invert
Total fall = grade (in/ft) × run (ft); downstream invert = upstream invert − total fall (e.g., 48 ft × ¼ in/ft = 12 in = 1.00 ft; 100.00' − 1.00' = 99.00')Grade expressed as percent slope
Percent slope = (rise in inches per foot ÷ 12 in) × 100 (e.g., ¼ in/ft → (0.25 ÷ 12) × 100 = 2.08%)Cylindrical tank volume and gallon capacity
V = π × r² × h (r = ½ diameter); gallons = V (ft³) × 7.48 gal/ft³; for a partly filled tank use the actual water height (e.g., π × 2² × 6 = 75.4 ft³ → 564 ≈ 565 gal; half height: π × 2² × 3 = 37.7 ft³ → 282 gal)Water contained in a length of pipe
Area = π × r² (r in feet); Volume = area × length; gallons = volume × 7.48 (e.g., 2-in ID: π × (1/12)² = 0.0218 ft² × 100 ft = 2.18 ft³ × 7.48 = 16.3 gal)Cut length of threaded pipe between two fittings
Cut length = center-to-center − (fitting takeoff × 2) + (thread engagement × 2) (e.g., 42 − 4½ + 1 = 38½ in; 36 − 4 + 1 = 33.00 in)Water heater recovery rate (GPH)
Usable BTU/hr = input × efficiency; BTU per gallon = 8.33 lb/gal × temperature rise (°F); GPH = usable BTU/hr ÷ BTU per gallon (e.g., 30,000 ÷ 583.1 = 51.4 GPH)