Arizona ROC A-16 Waterworks (Commercial) Examination

When assembling a push-on joint for Ductile Iron Pipe (DIP) in a water distribution main per AWWA C600, which procedure is required to ensure a watertight seal without damaging the rubber gasket?

• AClean the socket and gasket groove, apply approved non-toxic vegetable lubricant to the s…
• BApply petroleum-based grease liberally to the gasket and spigot end
• CHeat the bell end with a propane torch to expand the socket prior to inserting the spigot
• DDrive the spigot home using a backhoe bucket directly against the pipe bell without align…

According to AWWA C600 standards, what is the minimum hydrostatic test pressure and duration required for newly installed ductile iron water mains?

• A1.0 times the working pressure for 30 minutes
• B1.5 times the working pressure at the lowest point (or at least 150 psi) for a minimum du…
• C1.25 times the maximum operating pressure for 1 hour
• D2.0 times the system design pressure for 24 hours

A contractor is hydrostatically testing a 2,000-foot section of 12-inch nominal diameter ductile iron pipe at a test pressure of 150 psi. Using the AWWA C600 allowable leakage formula L = (S * D * sqrt(P)) / 148,000, what is the maximum allowable leakage rate in gallons per hour (gph)?

• A0.98 gph
• B3.45 gph
• C1.99 gph
• D5.20 gph

A 16-inch water main operating at 100 psi makes a 45-degree horizontal bend. If the total hydrostatic thrust force generated is calculated as 15,400 lbs and the soil bearing capacity is 2,000 pounds per square foot (psf), what is the minimum required bearing area of the concrete thrust block against undisturbed soil?

• A3.85 sq ft
• B30.80 sq ft
• C15.40 sq ft
• D7.70 sq ft

In hydraulic network calculations, how does the Hazen-Williams roughness coefficient (C-factor) affect pipe friction head loss?

• AA higher C-factor represents a smoother interior pipe surface, resulting in lower frictio…
• BA higher C-factor represents a rougher interior surface, resulting in higher friction hea…
• CThe C-factor only applies to open-channel flow and has no effect on pressurized pipes
• DFriction head loss is directly proportional to the square of the C-factor

What is the continuous pressure rating for AWWA C900 PVC pipe designated as SDR 18 when evaluated with a hydrostatic design basis (HDB) of 4,000 psi?

• A150 psi
• B235 psi
• C200 psi
• D305 psi

What is the required heater plate surface temperature range for making butt-fusion joints on High-Density Polyethylene (HDPE) water mains per ASTM F2620?

• A250°F to 300°F
• B325°F to 375°F
• C400°F to 450°F
• D500°F to 550°F

When performing main disinfection using the continuous-feed method under AWWA C651, what initial chlorine concentration must be introduced, and what minimum free chlorine residual must remain after 24 hours?

• A10 mg/L initial, 2 mg/L residual
• B25 mg/L initial, 10 mg/L residual
• C100 mg/L initial, 50 mg/L residual
• D50 mg/L initial, 25 mg/L residual

Under AWWA C651, what chlorine concentration and minimum contact time are required when using the slug method for main disinfection?

• A100 mg/L for 3 hours
• B50 mg/L for 6 hours
• C25 mg/L for 12 hours
• D200 mg/L for 30 minutes

Which restriction applies to the use of the tablet method for main disinfection under AWWA C651?

• AIt can be used on mains of any diameter up to 48 inches regardless of water cleanliness
• BIt is restricted to mains 24 inches in diameter or smaller and requires clean, dry pipe c…
• CTablets must be dissolved in petroleum distillate prior to attachment to pipe crowns
• DIt requires flushing the main at 10 ft/s before introducing water to fill the pipe

When installing a dry-barrel fire hydrant, what feature allows water to drain from the barrel after the main valve is closed to prevent freezing?

• AA continuously open 2-inch bypass pipe connected directly to the sewer main
• BA manual hand pump installed inside the steamer nozzle cap
• CAn automatic weep/drain hole at the base of the hydrant barrel surrounding a clean gravel…
• DA check valve fitted onto the steamer outlet nozzle

Which type of valve is designated by AWWA C509/C515 for distribution mains because it provides a smooth, unobstructed waterway bottom without a grit-trapping seat pit?

• ADouble-disc gate valve
• BSwing check valve
• CGlobe control valve
• DResilient-seated gate valve

What design characteristic of AWWA C504 butterfly valves must contractors consider when installing them in water transmission lines?

• AThe valve disc remains in the flow stream even when fully open, creating minor head loss
• BButterfly valves can only be installed in vertical riser pipes
• CThe valve disc retracts completely into an external bonnet housing outside the waterway
• DThey cannot be operated against differential pressure exceeding 10 psi

To prevent excessive friction head loss, scouring of pipe linings, and hydraulic surge pressure (water hammer), what is the maximum recommended design velocity for normal operating conditions in water distribution mains?

• A2.0 ft/s
• B5.0 ft/s
• C12.0 ft/s
• D20.0 ft/s

A 10-inch internal diameter water main carries a flow rate of 1,200 gallons per minute (gpm). What is the mean water velocity inside the pipe? (1 cfs = 448.83 gpm)

• A2.45 ft/s
• B6.85 ft/s
• C4.90 ft/s
• D9.80 ft/s

Which device is specifically installed at strategic high points on water distribution mains to release trapped air and prevent pipeline collapse caused by negative sub-atmospheric pressure during rapid draining?

• APressure reducing valve (PRV)
• BResilient wedge gate valve
• CDouble-check backflow preventer
• DCombination air release and vacuum relief valve

Where should automatic air release valves be positioned along a water transmission pipeline profile?

• AAt high points (crests) along the pipeline profile and major changes in downward slope
• BAt low points where heavy sediment collects
• CDirectly downstream of every pressure reducing valve without exception
• DExclusively inside wet well pump sumps

According to Arizona Department of Environmental Quality (ADEQ) Engineering Bulletin No. 10, what are the minimum required parallel horizontal and vertical clearances between a parallel water main and a sanitary sewer line?

• A3 feet horizontal; 6 inches vertical
• B10 feet horizontal separation; 18 inches vertical clearance with the water main above the…
• C6 feet horizontal; 12 inches vertical
• D20 feet horizontal separation; 36 inches vertical clearance with the sewer line above the…

When installing a 2-inch service lateral connection onto a 6-inch C900 PVC water main under pressure (hot tap), why is a wide-band stainless steel tapping saddle required instead of direct tapping?

• ADirect tapping is prohibited on all metallic pipes but mandatory on plastic pipes
• BTapping saddles convert AC voltage to DC current to prevent pipe rust
• CDirect tapping PVC pipe creates localized stress concentrations that can cause catastroph…
• DTapping saddles increase water flow velocity into the service lateral by 50%

At what angle off the vertical top axis of a water main should a corporation stop tap be installed?

• ADirectly on top (0 degrees vertical) to catch high-velocity surface water
• BAt a downward 45-degree angle below the pipe springline
• CDirectly on the pipe bottom (180 degrees) for maximum head pressure
• DAt a 45-degree angle above horizontal to prevent air binding and bottom sediment entry

What minimum water velocity must be achieved during main flushing per AWWA C651 to effectively scour foreign material, sand, and construction debris from newly laid water mains?

• A3.0 ft/s
• B1.0 ft/s
• C7.5 ft/s
• D15.0 ft/s

In locations where unstable soil cannot support concrete thrust blocks, which mechanical pipe restraint system is used to lock mechanical joint fittings to ductile iron pipe?

• ASolvent weld PVC cement couplers
• BWedge-action mechanical joint retainer glands (such as MEGALUG)
• CLead-oakum caulked bell joints
• DStandard slip-on rubber gaskets without tie-rods

Which chemical neutralizing agent is commonly used by contractors to dechlorinate super-chlorinated water flushed from disinfected water mains prior to discharging into storm drains?

• ACopper sulfate crystals
• BCalcium chloride pellets
• CSodium thiosulfate or ascorbic acid (Vitamin C)
• DSulfuric acid solution

During construction of a new water main, what backflow assembly must be installed on the temporary jumper connection supplied from an existing municipal water main?

• AAtmospheric vacuum breaker (AVB)
• BDouble check valve assembly (DCVA)
• CSingle spring-loaded check valve
• DReduced pressure zone (RPZ) backflow preventer assembly

Under OSHA 29 CFR 1926 Subpart P, what is the minimum unconfined compressive strength required for cohesive soil to be classified as Type A soil?

• A1.5 tons per square foot (tsf)
• B1.0 ton per square foot (tsf)
• C0.5 tons per square foot (tsf)
• D2.5 tons per square foot (tsf)

Which soil type classification applies to granular cohesionless soils such as gravel, sand, submerged soil, or unstable rock under OSHA 1926 Subpart P?

• AStable Rock
• BType C Soil
• CType B Soil
• DType A Soil

What is the maximum allowable slope angle (expressed as Horizontal to Vertical ratio) for an excavation in Type A soil open 24 hours or less and 12 feet or less in depth?

• A1 : 1 (45 degrees)
• B3/4 : 1 (53 degrees)
• C1/2 : 1 (63 degrees)
• D1-1/2 : 1 (34 degrees)

What is the maximum allowable slope angle for an excavation dug in Type C soil under OSHA 1926 Subpart P?

• A3/4 : 1 (53 degrees)
• B1 : 1 (45 degrees)
• C2 : 1 (26 degrees)
• D1-1/2 : 1 (34 degrees)

At what depth does OSHA 1926.652 require a protective system (sloping, benching, shoring, or shielding) in an excavation unless made entirely in stable rock?

• A5 feet or deeper
• B4 feet or deeper
• C3 feet or deeper
• D8 feet or deeper

According to OSHA 1926.651(c)(2), what is the maximum allowable lateral travel distance for workers inside a trench 4 feet or more in depth to reach a ladder, ramp, or stairway?

• A10 feet
• B25 feet
• C50 feet
• D100 feet

How far back from the edge of an excavation must excavated spoil piles, equipment, and loose materials be kept per OSHA 1926.651(j)(2)?

• AAt least 1 foot
• BAt least 4 feet
• CAt least 2 feet
• DAt least 6 feet

Under Arizona Revised Statutes (A.R.S. § 40-360.21-.32) and Arizona 811 (Blue Stake) rules, how much advance notice must an excavator provide to underground facility operators prior to starting trenching operations?

• A12 hours advance notice
• B10 working days advance notice
• C5 calendar days advance notice
• DAt least 2 working days advance notice (excluding weekends and legal holidays)

In flexible water pipe trench installation (such as PVC or HDPE), which embedment zone is most critical for providing side support to prevent pipe deflection under earth loads?

• AHaunching zone
• BFoundation layer
• CSecondary initial backfill
• DFinal backfill surface cap

When backfilling a water main trench located within a public street right-of-way, what minimum soil compaction density is typically specified based on ASTM D1557 (Modified Proctor)?

• A80% Modified Proctor density
• B95% Modified Proctor density
• C90% Modified Proctor density
• D85% Modified Proctor density

When a trench shield (trench box) is used in combination with sloping above the shield, how far must the top of the trench shield extend above the vertical wall face?

• AFlush with the bottom of the slope
• BAt least 6 inches above the vertical side
• CAt least 18 inches above the top of the vertical side
• DAt least 36 inches above ground surface

Who is authorized under OSHA 1926 Subpart P to inspect excavation sites daily, identify soil hazards, and immediately stop work to eliminate cave-in risks?

• AAny employee on the job site
• BCity building inspector
• CRegistered Professional Engineer only
• DDesignated Competent Person

In mud rotary well drilling, what primary function does bentonite drilling fluid serve besides cooling the bit and bringing cuttings to the surface?

• AForming an impermeable filter cake (mud cake) on the borehole wall to prevent hole cave-i…
• BDissolving hard granite rock formations chemically
• CSterilizing the aquifer against all bacterial growth
• DPermanently cementing the lower screen section in place

Why is reverse-circulation rotary drilling frequently selected for constructing large-diameter commercial water supply wells in unconsolidated formations?

• ADrilling fluid flows down through the drill pipe and returns up the open annulus
• BClean water flows down the annulus under gravity and returns up inside the large drill pi…
• CIt uses high-pressure compressed air exclusively without water or mud
• DIt operates without a drill bit by using hydraulic water jets

What is a primary operational characteristic of cable-tool (percussion) well drilling?

• ARapid penetration rates in deep volcanic basalt formations
• BHigh-volume mud circulation to support 36-inch diameter boreholes
• CLifting and dropping a heavy drill stem and bit on a wire rope cable to crush formation r…
• DContinuous flight auger rotation requiring no water or bailing

According to Arizona Department of Water Resources (ADWR) Well Construction Rules (AAC R12-15-811), steel well casing installed in water wells must conform to which specification standard?

• ANon-reinforced corrugated culvert pipe
• BASTM A36 structural plate welded with copper rod
• CSchedule 40 cellular core ABS pipe
• DASTM A53, ASTM A139, or API Spec 5L

To minimize encrustation, corrosion, and friction head loss across a well screen, AWWA guidelines recommend limiting the water entrance velocity through screen slots to what maximum rate?

• A0.1 ft/s (0.03 m/s)
• B0.5 ft/s (0.15 m/s)
• C2.0 ft/s (0.61 m/s)
• D5.0 ft/s (1.52 m/s)

How is the grain size of an artificial gravel pack (filter pack) selected during commercial water well design?

• ABy using uniform coarse river cobbles ranging from 2 to 4 inches
• BBy taking 4 to 6 times the 30% or 50% retained size (d30 or d50) determined from sieve an…
• CBy selecting fine masonry sand matching local concrete mix sand
• DBy matching gravel pack grain size exactly to the pump impeller diameter

Under ADWR Well Construction Rules, what is the minimum required depth for the protective surface annular seal (grout) in a commercial water well?

• A5 feet
• B10 feet
• C20 feet
• D50 feet

When placing neat cement grout into the annular space of a water well casing, why must grout be pumped through a tremie pipe from the bottom of the seal upward?

• ATo allow grout to cool before reaching the surface
• BTo dissolve the well screen assembly during curing
• CTo push the casing deeper into the borehole via hydraulic pressure
• DTo prevent air entrapment, bridging, and dilution of the grout by standing water