General Requirements
5%of exam
Piping Protection
2%of exam
Freeze ProtectionNail PlatesVehicle ImpactDielectric Fittings
Piping Installation & Testing
3%of exam
Hanger SpacingDWV TestingCondensate DisposalApproved Joints
Fixtures, Faucets & Fittings
15%of exam
Fixture Flow RatesAccessible ClearancesFixture CountsScald Protection
Water Heaters
10%of exam
T&P Relief ValvesDrain PansThermal ExpansionCombustion Air
Water Supply & Distribution
14%of exam
Fixture Unit SizingBackflow PreventionAir GapsPipe Materials
Sanitary Drainage
18%of exam
Vents
15%of exam
Vent SizingTrap Arm DistanceVent TypesAir Admittance Valves
Traps, Interceptors & Special Piping
11%of exam
Storm Drainage
7%of exam
Roof Drain SizingSecondary DrainageStorm MaterialsSystem Separation
Quick Facts
- Exam
- P2
- Credential
- Commercial Plumbing Inspector
- Questions
- 60 multiple-choice
- Time
- 2.5 hours
- Pass Score
- 75 (scaled)
- Format
- Open book
- Code Basis
- 2024 IPC + IFGC
- Accessibility Std
- ICC A117.1-2017
Inspection Sequence Check
- Work about to be concealed→Rough-in inspection first
- Piping installed below grade→Underground inspection first
- All systems fully complete→Final inspection
- DWV before it is covered→Water or air test
- Gas piping before use→3 psi for 10 min
Code Official & Permits
- Code official
- Enforces & interprets code
- Construction docs
- Required when official demands
- Rough-in inspection
- Before work is concealed
- Underground inspection
- Before backfill covers piping
- Final inspection
- After all systems tested
- Listed materials
- Third-party tested and labeled
Piping Protection Rules
- Water service depth
- 12 in minimum below grade
- Frost protection depth
- 6 in below frost line
- Stud clearance zone
- Under 1-1/4 in needs plate
- Shield plate gauge
- 16 gauge, 0.0575 in steel
- Vehicle impact zones
- Guard post or bollard required
- Dissimilar metal joints
- Dielectric union prevents corrosion
Installation & Testing
- Copper DWV hanger
- 10 ft horizontal spacing
- PVC DWV hanger
- 4 ft horizontal spacing
- DWV water test
- 10 ft head, 15 min
- DWV air test
- 5 psi for 15 min
- Condensate discharge
- Indirect waste connection only
Flush & Flow Limits
Water closets flush most, faucets sip water
WC 1.6 gpfUrinal 0.5 gpfLav 0.5-2.2 gpmShower 2.5 gpm
Fixture Flow & Flush Rates
- Public lavatory faucet
- 0.5 gpm at 60 psi
- Private lavatory faucet
- 2.2 gpm at 60 psi
- Showerhead limit
- 2.5 gpm at 80 psi
- Water closet flush
- 1.6 gpf maximum
- Urinal flush
- 0.5 gpf maximum
- Public metering faucet
- 0.25 gal per cycle
A117.1 Accessible Heights
Seat, rim, and grab bar each keep their own range
Seat 17-19 inRim 34 in maxGrab bar 33-36 inKnee space 27 in
Fixture & Accessible Clearances
- WC front clearance
- 21 in minimum
- WC centerline to wall
- 15 in minimum
- WC centerline spacing
- 30 in apart minimum
- Accessible WC centerline
- 16-18 in from wallA117.1
- Accessible WC seat height
- 17-19 in above floorA117.1
- Grab bar height
- 33-36 in above floorA117.1
- Accessible lavatory rim
- 34 in maximum heightA117.1
- Lavatory knee clearance
- 27 in high, 8 deep
Water Heater Safety Devices
- T&P discharge height
- 6 in max above floor
- T&P valve rating
- Match water heater input
- Drain pan trigger
- Leakage would damage building
- Drain pan pipe
- 3/4 in minimum diameter
- Thermal expansion device
- Required on closed systems
- Public lav tempered water
- 110 F maxASSE 1070
- Shower/tub delivery
- 120 F maxASSE 1016
Water Heater Venting & Air
- Indoor combustion air
- 50 cu ft per 1000 Btu
- Zero-clearance heaters
- Only if listed for it
- Solar freeze protection
- Drain-back or nontoxic fluid
- Bathing facility trigger
- Overnight-stay occupancies only
Hazard Level to Device
High hazard needs RP, low hazard needs double check
High = RP/RPZLow = double checkAir gap = universal fix
RP vs Double Check
RP Assembly
- High hazard
- Contamination risk
- Continuous pressure ok
Double Check
- Low hazard
- Pollution risk only
Hazard level decides device
Backflow Device Selector
- High hazard, continuous pressure→RP/RPZ assembly
- Low hazard, continuous pressure→Double check valve
- Air gap achievable→Physical air gap
- Hose bibb, outdoors→Non-removable vacuum breaker
- Irrigation with chemical injection→RP or air gap
- PVB installed outdoors→12 in above outlet(Not continuous pressure)
Water Supply Sizing
- Public flushometer WC
- 10 water supply fixture units
- Tank-type public WC
- 5 water supply fixture units
- Private flushometer WC
- 2.5 water supply fixture units
- Min static pressure
- 15 psi, 20 for flushometers
- Max static pressure
- 80 psi before PRV required
- PRV side effect
- Creates a closed system
- Flushometer WC branch
- 1 in minimum size
- Hot water recirc trigger
- Over 50 ft developed length
Backsiphonage vs Backpressure
Backsiphonage
- Supply pressure drops
- Vacuum pulls water back
Backpressure
- Downstream pressure rises
- Pushes water upstream
Direction of pressure change
Backflow Prevention Devices
- High hazard cross-connection
- RP/RPZ assembly required
- Low hazard cross-connection
- Double check valve assembly
- Air gap, no wall
- 2x diameter, 1 in min
- Air gap, near wall
- 3x diameter, 1.5 in min
- PVB install height
- 12 in above highest outlet
- Hose bibb protection
- Non-removable vacuum breaker
- Chemical feed systems
- RP assembly or air gap
- Water hammer trigger
- Any quick-closing valve
Pipe Materials & Valves
- Underground water service
- Type K copper only
- Interior distribution copper
- Type L copper standard
- PEX tubing standard
- ASTM F877 or CSA B137.5
- Nonpotable pipe color
- Purple, marked lavender
- Full-open shutoff valves
- At service entry and heaters
Air Gap vs Air Break
Air Gap
- Physical vertical separation
- Required for food equipment
Air Break
- Below flood rim
- Not compliant for food
Food waste needs true gap
Drainage Fixture Unit Values
- Public WC, 1.6 gpf
- 4 dfu
- Public WC, over 1.6 gpf
- 6 dfu
- Urinal
- 2 dfu
- Public lavatory
- 1 dfu
- Kitchen sink
- 2 dfu
- Floor drain
- 2 dfu minimum
- Service sink
- 2 dfu
Building Drain vs Branch Table
Table 710.1(1)
- Building drains & sewers
- Sized by slope
Table 710.1(2)
- Branches & stacks
- Sized by pipe only
Match table to pipe type
Drain Sizing & Slope
- Slope, 2.5 in or less
- 1/4 in per ft
- Slope, 3 to 6 in
- 1/8 in per ft
- Slope, 8 in or larger
- 1/16 in per ft
- 4-in drain, 1/4 slope
- 216 dfu capacity
- Min building sewer size
- 3 in diameter
- Cleanout interval
- 100 ft maximum spacing
- Cleanout direction change
- Required over 45 degrees
- Cleanout minimum size
- Equals pipe, 4 in max
Special Drainage Systems
- Backwater valve trigger
- Rim below upstream manhole
- Sewage ejector discharge
- 2 in minimum size
- Grinder pump discharge
- 1-1/4 in minimum size
- Sump cover
- Gas-tight and vented
- Food equipment waste
- Air gap always required
- Double sanitary tee
- Prohibited for horizontal use
- Chemical waste material
- Acid-resistant, chemical-specific
Trap Arm Growth Pattern
Bigger trap arm allows a longer run to vent
1-1/4 in = 5 ft1-1/2 in = 6 ft2 in = 8 ft3 in = 12 ft4 in = 16 ft
Common Vent vs Circuit Vent
Common Vent
- Two fixtures only
- Same level connection
Circuit Vent
- Up to 8 fixtures
- One horizontal branch
Fixture count decides choice
Vent Type Selector
- Two fixtures, same level→Common vent
- Up to 8 fixtures→Circuit vent
- Drain also serves as vent→Wet vent
- Island sink, no wall→Loop or combo waste-vent
- Avoiding a roof penetration→AAV plus one open vent
Vent Sizing & Installation
- Min vent diameter
- 1-1/4 in absolute minimum
- Vent rise before offset
- 6 in above flood rim
- Vent through roof
- 6 in minimum above roof
- Vent near opening
- 10 ft, or 2 ft above
- Vent connection angle
- 45 degrees minimum from horizontal
- Horizontal vent slope
- 1/8 in per ft
- Vent stack trigger
- 5 or more branch intervals
Vent Types & Trap Arm
- Trap arm, 1-1/4 in
- 5 ft max to vent
- Trap arm, 1-1/2 in
- 6 ft max to vent
- Trap arm, 2 in
- 8 ft max to vent
- Trap arm, 3 in
- 12 ft max to vent
- Trap arm, 4 in
- 16 ft max to vent
- Common vent
- 2 fixtures, same level
- Circuit vent
- Up to 8 fixtures
- Wet vent
- Drain doubles as vent
- AAV requirement
- Needs one open-air vent
Grease vs Oil Interceptor
Grease Interceptor
- Food-service kitchens
- Sized by gpm flow
Oil Separator
- Garages & fuel facilities
- Sized by drainage area
Food vs vehicle waste
Interceptor & Waste Selector
- Food-service grease waste→Grease interceptor
- Vehicle or fuel service→Oil separator
- Lab acid or chemical waste→Neutralization tank
- Chemical feed cross-connection→RP backflow device
- Medical or oxygen piping→Follow NFPA 99 or 55
Trap Rules
- Trap seal depth
- 2 to 4 in
- Fixture-to-weir drop
- 24 in maximum
- Prohibited traps
- S-traps, drum, and bell traps
- Each fixture rule
- Separate, self-scouring trap required
S-Trap vs P-Trap
S-Trap
- Self-siphons seal
- Prohibited by IPC
P-Trap
- Vented trap arm
- Code-required design
S-trap always fails inspection
Interceptors & Medical Gas
- Grease interceptor sizing
- By gpm drainage flow
- Oil separator use
- Garages and fuel facilities
- Lab acid waste
- Neutralize before sanitary sewer
- Medical gas standard
- NFPA 99
- Bulk oxygen standard
- NFPA 55
- Medical gas pipe
- Cleaned Type K or L copper
Storm Drainage Rules
- Design rainfall basis
- 100-year, 1-hour rate
- Secondary drain trigger
- Parapet could trap water
- Subsoil drain discharge
- Storm system, never sanitary
- Storm/sanitary connection
- Never permitted, always separate
- Storm pipe materials
- Own table, not sanitary table
Common Traps
Air Gap vs Air Break
Gap is above rim ≠ Break is below rim
S-Trap Looks Like P-Trap
S-trap self-siphons ≠ P-trap holds seal
Grease vs Oil Interceptor
Grease serves kitchens ≠ Oil serves vehicles
Backsiphonage vs Backpressure
Siphonage is a pressure drop ≠ Backpressure is a pressure push
Stack Vent vs Vent Stack
Stack vent extends the stack ≠ Vent stack is separate pipe
Double Sanitary Tee Rules
Banned for horizontal use ≠ Allowed vertical with conditions
Building Drain vs Branch Table
Drain table uses slope ≠ Branch table uses pipe size only
Last Minute
- 1.60 questions, 2.5 hour limit
- 2.Open book: 2024 IPC required
- 3.Passing score is 75 scaled
- 4.High hazard always needs RP
- 5.Trap seal is 2-4 in
- 6.Never connect storm to sanitary
- 7.S-traps are always prohibited
- 8.Food waste needs true air gap
- 9.PRV always requires expansion tank
- 10.Tab your IPC tables first
- 11.Water Supply and Drainage are 32%
- 12.Bring only approved code references
Buy on AmazonSame family resources
Explore More ICC Certifications
Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.
More From This Family
Videos and articles for deeper review.
VideoFREE ICC P2 Exam Guide 2026: Commercial Plumbing Inspector Study PlanThis examVideoFREE ICC B1 Residential Building Inspector Exam Guide 2026 (2024 IRC, 60 Qs, Pass First Try)VideoFREE ICC B2 Commercial Building Inspector Exam Guide 2026 (2024 IBC, 80 Qs, Pass First Try)VideoFREE ICC Property Maintenance & Housing Inspector Guide 2026 (Exam 64, IPMC 2024, Pass First Try)ArticleFREE ICC P2 Exam Guide 2026: Commercial Plumbing Inspector Study Plan12 min readArticleFREE ICC B2 Commercial Building Inspector Exam Guide 2026 (2024 IBC, 80 Qs, Pass First Try)15 min readArticleFREE ICC Property Maintenance & Housing Inspector Guide 2026 (Exam 64, IPMC 2024, Pass First Try)26 min readArticleFREE ICC B1 Residential Building Inspector Exam Guide 2026 (2024 IRC, 60 Qs, Pass First Try)27 min read