10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The WA-JP exam has 150 questions and runs 4 hours 30 minutes.
These 10 free WA-JP questions are organized by exam domain, so you can see how each part of the Washington Journey Level Plumber Certification Exam blueprint is tested. Reveal the answer and explanation under each question.
Domain 1: Journey Level code and general trade knowledge
Question 1
After a check valve is added at a building's water service, a plumber investigates intermittent high pressure downstream of a pressure-reducing valve set to 58 psi. Pressure stays at 58 psi with the storage water heater off, even when no fixtures are used. During a recovery cycle with every fixture closed, it gradually rises to 132 psi. Briefly opening a faucet returns it to 58 psi. Which condition best explains this pattern?
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Correct answer: B - Thermal expansion without effective expansion control
Question 2
An owner is replacing a residential bathtub with a 34-by-62-inch shower receptor and one showerhead rated at 2.0 gpm. A 2-inch waste line is not readily available. The existing 1-1/2-inch waste outlet, tailpiece, trap, and trap arm are sound and otherwise compliant. One contractor says that every tub-to-shower conversion requires a new 2-inch drain. What does Washington's 2015 UPC exception permit in this situation?
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Correct answer: A - Retaining the 1-1/2-inch assembly with approval from the authority having jurisdiction.
Question 3
A dishwasher drains normally into a food-waste disposer through a hose secured in a high loop beneath the countertop. There is no dishwasher air-gap fitting. The homeowner argues that the high loop is enough because the sink has never backed up. The sink trap and vent are correct. To meet Washington's 2015 UPC drainage requirements, the plumber needs to:
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Correct answer: A - Install an approved dishwasher air-gap fitting at the required elevation.
Question 4
A closed-loop hot-water boiler contains water only, with no chemical additives. Its permanent potable makeup connection will remain pressurized and will not use an air-gap arrangement. For the backflow-protection requirement in Washington's 2015 UPC amendment, the equipment schedule must specify:
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Correct answer: C - A reduced-pressure-principle backflow assembly
Question 5
While a storage water heater is heating, a plumber finds a metal cap on the end of its temperature-and-pressure relief discharge pipe. The owner installed the cap after repeated dripping. The heater's energy shutoff is safely accessible. What takes priority before investigating the cause of the dripping?
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Correct answer: B - Shut off the energy supply before correcting the blocked relief discharge.
Question 6
Two listed storage water heaters are proposed for a new four-bedroom dwelling with 2-1/2 bathrooms. A 40-gallon model has a 71-gallon first-hour rating; a 65-gallon model has a 64-gallon first-hour rating. Installation requirements are otherwise satisfied, and no alternative sizing method is proposed. Applying Washington's 2015 UPC Table 501.1, which statement is correct?
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Correct answer: A - Only the 40-gallon model meets the required first-hour rating.
Domain 2: Waste and Vent Journey Level Drawings
Question 7
On a new commercial project, a common horizontal drain receives four water closets rated at 1.28 gallons per flush and four lavatories. The connected load is 20 drainage fixture units (DFUs). The proposed 3-inch drain slopes 1/4 inch per foot, and its tabulated horizontal capacity is 35 DFUs. Which installation meets the minimum drainage-sizing requirements of the 2015 UPC and Washington amendments?
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Correct answer: D - Use a 4-inch line at the proposed grade.
Question 8
The largest required building sewer is 4 inches. The only existing roof vents are a 3-inch vent on the gravity drainage system and a 2-inch vent on a sealed sewage-ejector basin. The ejector and its check valve interrupt the air path between the basin vent and the building sewer. Individual fixture venting is satisfactory. Using nominal circular areas for the 2015 UPC aggregate-vent check, what is the smallest additional vent directly connecting the gravity system to atmosphere that provides enough qualifying area?
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Correct answer: D - 3 inches
Domain 3: Water Sizing Journey Level Drawings
Question 9
Size a building supply using 2015 UPC Table 610.4. The meter and street service are both 1 inch and will remain unchanged. Minimum source pressure is 66 psi; the highest outlet is 24 feet above the meter; an additional treatment-device loss is 12 psi. Developed length to the most remote outlet is 130 feet, and demand is 24 water-supply fixture units (WSFUs). For this meter/service combination, the relevant table capacities are:
30-45 psi: 1-inch pipe carries 25 WSFUs at 100 feet and 20 at 150 feet; 1-1/4-inch pipe carries 32 at 150 feet; 1-1/2-inch pipe carries 56 at 150 feet.
46-60 psi: 1-inch pipe carries 30 WSFUs at 150 feet.
Which choice uses the correct pressure group and length column and the smallest adequate listed pipe?
A service pipe supplies a private bathroom, then divides into a cold fixture branch and a water-heater feed. Hot water from that heater serves the bathroom's lavatory and tub; the water closet is cold-only. A sizing worksheet correctly applies 75% of each dual-supplied fixture's Table 610.3 value to its separate hot and cold branches. The designer then adds those two branch totals to size the upstream service. How should the service load instead be established?
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Correct answer: C - Count each fixture's full listed value once, including the cold-only water closet.
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