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-ConnectionvsLow Hazard Cross-Connection
High hazard involves contamination (substances that could cause illness or death), while low hazard involves pollution (aesthetically objectionable but not dangerous to health).
IPC, Table 608.1 footnotesContaminationvsPollution
Contamination is classified as a high-hazard condition posing a health risk; pollution is a low-hazard condition that degrades water quality aesthetically but poses no direct health hazard.
IPC, Table 608.1 footnotes and Section 202 referencesBranch Length MethodvsLongest Length Method
The Branch Length Method sizes each branch using the actual distance from meter to that branch's most remote outlet, reducing conservatism compared to the Longest Length Method, which applies the single overall longest system length to every section.
2018 International Fuel Gas Code (IFGC), Appendix A, Section A.3.2Reduced Pressure Principle Backflow Prevention AssemblyvsDouble Check Valve Assembly
A reduced pressure principle assembly is approved for both high- and low-hazard applications and protects against both backpressure and backsiphonage, whereas a double check valve assembly is approved for low-hazard applications only.
Uniform Plumbing Code, Table 608.1Full-Open ValvevsShutoff Valve
Full-open valves are required at specific locations such as water heaters and riser pipes, while shutoff valves are required at sillcocks, appliances, and fixture supplies (other than bathtubs and showers in one- and two-family residences).
IPC 606.1(8)Wet VentvsDry Vent
A wet vent simultaneously carries the discharge of one fixture while venting another, whereas a dry vent carries only air and no fixture discharge.
Pressure Vacuum Breaker AssemblyvsBarometric Loop
A pressure vacuum breaker assembly must be installed at least 12 inches above all downstream piping and outlets, while a barometric loop must extend vertically to a height of at least 35 feet.
Uniform Plumbing Code, Section 608.14.5Tee-Wye DWV FittingvsStandard Tee DWV Fitting
A tee-wye has two long allowances and one short allowance with a built-in ¼-inch-per-foot slope on the branch, whereas a standard tee has three equal allowances and no built-in slope.
Mathematics For Plumbers And Pipefitters, Unit 23Type C SoilvsStable Rock
Type C soil (e.g., submerged or freely seeping soil) is the least stable category and always requires a protective system for excavations 5 feet or more in depth, while stable rock requires no protective system regardless of depth.
29 CFR 1926, Subpart P, §1926.652(a)(1) and Appendix APersonal Fall Arrest SystemvsGuardrail System
A personal fall arrest system arrests a worker after a fall begins and requires retraining when first introduced; a guardrail system is a passive barrier that prevents falls and does not require the worker to wear any equipment.
29 CFR 1926, Subpart M, §1926.503(c)(2)General Requirement (IPC)vsSpecific Requirement (IPC)
Where a conflict exists between a general and a specific requirement in the IPC, the specific requirement governs; where different sections require different materials or methods, the most restrictive governs.
International Plumbing Code 2018, Page 1 (Section 102.1)Potable Water PipingvsNonpotable (Reclaimed/Gray/Rain) Water Piping
Potable water piping has no mandatory color designation under the cited code sections, while nonpotable reclaimed, rain, and gray water distribution piping must be purple in color.
Uniform Plumbing Code, Sections 608.9.2 and 608.9.2.1Key Terms
Permit Expiration (IPC Section 106.5.3) International Plumbing Code 2018, Page 6 (Section 106.5.3)
A permit becomes null and void if work is not commenced within 180 days from the date of issuance.
Penalty for Commencing Work Without a Permit (IPC Section 106.6.1) International Plumbing Code 2018, Page 7 (Section 106.6.1)
Any person who begins plumbing work before obtaining a permit is subject to an additional fee of 100 percent of the usual permit fee on top of the required permit fees.
Pressure-Reducing Valve Failure Mode (IPC Section 604.8.1) IPC 2018, Section 604.8.1
A pressure-reducing valve installed on a building water supply shall be designed to remain open (fail-open) in the event of valve failure to ensure uninterrupted water flow.
Thermal Expansion Control Device (UPC Section 607.3) Uniform Plumbing Code, Section 607.3
Where a storage water heater's cold water supply passes through a check valve, pressure-reducing valve, or backflow preventer, a thermal expansion control device must be installed on the cold water supply pipe downstream of all such devices.
Low-Pressure Cutoff for Booster Pumps (UPC Section 606.5.5) Uniform Plumbing Code, Section 606.5.5
A low-pressure cutoff must be installed on all booster pumps to prevent creation of a vacuum or negative pressure on the suction side when suction-side pressure drops to 10 psi or less.
Maximum Hot Water Piping Developed Length (UPC Section 607.2) Uniform Plumbing Code, Section 607.2
The developed length of hot or tempered water piping from the source to fixtures requiring hot or tempered water shall not exceed 50 feet.
Tempered Water Maximum Temperature (UPC Section 607.1.2) Uniform Plumbing Code, Section 607.1.2
Tempered water supplied through a water temperature limiting device conforming to ASSE 1070 shall not exceed 110°F (43°C).
Demand Recirculation Cold Water Temperature Limit (UPC Section 607.2.1.2) Uniform Plumbing Code, Section 607.2.1.2
The control on a demand recirculation pump must limit the temperature of water entering the cold water piping to a maximum of 104°F (40°C).
Prohibited Piping Reuse (UPC Section 608.11) Uniform Plumbing Code, Section 608.11
Piping that has been used for any purpose other than conveying potable water shall not be used for conveying potable water.
Asbestos Permissible Exposure Limit — TWA (29 CFR 1926.1101(c)(1)) 29 CFR 1926, Subpart Z, §1926.1101(c)(1) and (i)(1)
The 8-hour time-weighted average permissible exposure limit for airborne asbestos is 0.1 fiber per cubic centimeter of air; protective clothing is required when this limit is exceeded.
Employee Rotation — Asbestos (29 CFR 1926.1101(g)(3)(iv)) 29 CFR 1926, Subpart Z, §1926.1101(g)(3)(iv)
Employee rotation as a means of reducing employee exposure to asbestos is specifically prohibited under OSHA's construction asbestos standard.
Fall Protection at Excavation Edges (29 CFR 1926.501(b)(7)(i)) 29 CFR 1926, Subpart M, §1926.501(b)(7)(i)
Employees at the edge of an excavation 6 feet or more in depth must be protected by guardrail systems, fences, or barricades when the excavation is not readily visible due to plant growth or other visual barriers.
Water-Hammer Arrestor (UPC Section 604.9) Uniform Plumbing Code, Section 604.9
A water-hammer arrestor conforming to ASSE 1010 shall be installed wherever quick-closing valves are utilized in a water supply system.
Wet Vent
A wet vent is a pipe that simultaneously serves as the drain for one fixture and the vent for one or more other fixtures, commonly used for a single bathroom group.
Island (Loop) Vent
An island or loop vent is used for fixtures (such as island kitchen sinks) that have no adjacent wall for a conventional vertical dry vent, routing the vent up, over, and back below the flood rim to connect to a vented drain.
Static Water Pressure Constant
Static water pressure is calculated using the constant 0.433 psi per foot of vertical head (e.g., 46 ft of elevation head ≈ 20 psi).
Formulas to Know
Static Water Pressure from Elevation Head
Pressure (psi) = Height (ft) × 0.433 psi/ftElevation Head Required for a Given Pressure
Height (ft) = Pressure (psi) ÷ 0.433 psi/ftNatural Gas Capacity Correction for Specific Gravity
Adjusted Capacity = Table Capacity (at SG 0.60) × Gravity Factor (from Table A.2.4)