InterNACHI Certified Pool & Spa Inspector

Which residential pool construction type uses a continuous sprayed mix of cement, sand, and water shot through a hose at high velocity against steel reinforcement?

• AVinyl-liner pool over a sand bottom
• BGunite (pneumatically applied concrete) pool
• CFiberglass one-piece shell pool
• DStainless steel modular pool

An inspector observes a pool where the interior surface is a single, one-piece molded shell with a smooth, gel-coated finish. Which construction type is this MOST consistent with?

• AConcrete pool with plaster finish
• BVinyl-liner pool
• CFiberglass pool
• DTile-finished gunite pool

What is the typical thickness range of a residential vinyl pool liner?

• A0.005 to 0.010 inch
• B20 to 30 mil (0.020 to 0.030 inch)
• C1/4 to 1/2 inch
• D1 to 2 inches

A residential saltwater pool produces its own chlorine through which process?

• ADirect evaporation of salt into the pool water
• BElectrolysis of dissolved sodium chloride to generate hypochlorous acid
• CBacterial conversion of sodium to chlorine compounds
• DMechanical agitation that releases chlorine gas from salt

Which statement BEST describes a residential saltwater pool compared with a traditional freshwater chlorinated pool?

• AThe water is chlorine-free and uses salt as the sanitizer
• BThe water still contains chlorine, but it is generated on-site from dissolved salt
• CThe pool requires no sanitation chemistry monitoring
• DSalt replaces all pool water chemistry parameters

What is the typical salt concentration maintained in a residential pool served by a saltwater chlorine generator?

• AAbout 35,000 ppm (similar to sea water)
• BAbout 2,500 to 3,500 ppm
• CAbout 200 to 400 ppm
• DAbout 50 to 100 ppm

Which of the following defects is MOST commonly seen in a concrete/gunite pool but rarely seen in a fiberglass pool?

• ASpider crack patterns and surface delamination in the plaster
• BA factory gel-coat blister
• CA delivery-related transport crack at the rim
• DLiner wrinkles along the floor

An inspector notes that a fiberglass pool has been installed without proper backfill compaction. What problem is MOST likely to develop?

• AIncreased chlorine demand
• BBulging or floor deflection as the unsupported shell flexes under load
• CVinyl liner stretching
• DPlaster discoloration

During a winter inspection of a vacant fiberglass pool, the inspector observes the shell appears to have lifted out of the ground several inches at one end. What is the MOST likely cause?

• AHydrostatic uplift due to high groundwater after the pool was drained
• BExcessive cyanuric acid in the water
• CA heat-pump heater left running
• DSalt cell scaling

What is the primary purpose of a hydrostatic relief valve in a concrete pool?

• ARelieve excessive air pressure in the filter
• BAllow groundwater into the empty pool shell to prevent uplift
• CEqualize pH between the pool and groundwater
• DDischarge chlorinated water to the storm drain

An inspector finds a residential portable spa (hot tub). Which feature distinguishes a portable spa from an in-ground spa for inspection purposes?

• APortable spas have no jets
• BA portable spa is a self-contained, factory-built unit with integrated equipment, typical…
• CPortable spas always require gas heating
• DPortable spas operate without GFCI protection

Which type of pool construction is MOST commonly used for commercial/competition pools because it can be built to any shape and depth?

• AVinyl-liner over wood-panel walls
• BFiberglass one-piece shells
• CCast-in-place or shotcrete reinforced concrete
• DAbove-ground bolted steel

An inspector finds heavy white scale at the waterline of a saltwater pool and on the salt cell. What chemistry condition is the MOST likely cause?

• ALow pH and low calcium hardness
• BHigh pH combined with high calcium hardness causing calcium carbonate scaling
• CExcessive cyanuric acid
• DCombined chlorine

Which pool construction type is the MOST sensitive to ground movement and freeze/thaw cycles, with cracking as a primary inspection concern?

• AVinyl-liner pool (the liner accommodates movement)
• BFiberglass pool (the resilient shell flexes)
• CConcrete/gunite pool (rigid shell that can crack with ground movement)
• DAbove-ground pool (the framing flexes freely)

Which pool filter type typically achieves the FINEST filtration (smallest micron rating) of common residential filters?

• AHigh-rate sand filter
• BCartridge filter
• CDiatomaceous earth (DE) filter
• DBag filter on suction side

A pool sand filter requires routine 'backwashing.' What does backwashing do?

• AReverses pump rotation to clean the impeller
• BReverses flow through the filter media to flush out trapped debris to waste
• CSterilizes the sand with chlorine gas
• DRemoves air from the pump basket

An inspector notes that the filter pressure gauge reads 8-10 psi HIGHER than the clean baseline marked by the owner. What does this typically indicate?

• ALow water level in the pool
• BThe filter is dirty and needs backwashing or cleaning
• CA failed circulation pump
• DAn overheated heater

Which residential pool heater type uses the refrigeration cycle to extract heat from ambient air?

• ANatural-gas heater
• BPropane heater
• CHeat-pump (electric) pool heater
• DSolar mat heater

Which heater type generally has the LOWEST efficiency below approximately 50°F outdoor air temperature?

• ANatural-gas heater
• BHeat-pump pool heater
• CPropane heater
• DElectric resistance heater

A natural-gas pool heater has a soot-stained exterior burner door, yellow flame tipping, and visible scale on the heat exchanger. What is the MOST appropriate inspection action?

• AReport normal operation — soot is decorative
• BRecommend service by a qualified gas-appliance technician; the heater shows signs of comb…
• CDisable the heater permanently
• DRecommend installing a heat pump as the only option

Modern variable-speed pool pumps are widely adopted PRIMARILY because they:

• AProvide higher peak flow than single-speed pumps
• BReduce energy consumption by operating at lower speeds during longer filtration runs
• CEliminate the need for filters
• DAlways produce less noise at full speed

An inspector observes that a pool pump strainer pot (hair-and-lint basket) is missing its lid. What is the MOST appropriate report finding?

• ANo issue — the lid is decorative
• BDefect: the pump will lose prime, can run dry and burn out, and the open suction is a saf…
• CDefect only if it is a saltwater pool
• DNo issue if the pump is variable-speed

Which statement is TRUE regarding diatomaceous earth (DE) filters and the environment?

• ADE backwash water can typically be discharged directly to a storm sewer with no restricti…
• BDE is non-toxic and has no discharge concerns
• CMany jurisdictions require DE backwash water to be discharged to a sanitary sewer or a se…
• DDE filters do not produce backwash water

A residential pool 'automation' controller typically:

• AReplaces the need for water chemistry monitoring
• BControls pump speed, valve actuators, heater setpoint, lighting, and feature timers from…
• CGenerates chlorine without a salt cell
• DIs required by all building codes

What is the function of a check valve between the chlorine feeder/erosion chlorinator and the pump?

• APrevent concentrated chemicals from back-siphoning into the pump or filter when the pump…
• BMaintain pH automatically
• CReplace the strainer basket
• DBoost pump pressure

Which equipment component is responsible for transferring heat from the gas or refrigerant side to the pool water in a heater?

• ASkimmer weir
• BHeat exchanger (typically cupronickel, copper, or stainless tubes)
• CPump impeller
• DFilter media

An inspector notes a residential pool gas heater installed in a recessed alcove with poor ventilation. What is the PRIMARY safety concern?

• AInsufficient combustion air leading to incomplete combustion and possible CO accumulation
• BExcessive pump pressure
• CLow water chlorine demand
• DVinyl-liner overheating

Which equipment defect is MOST often associated with corroded electrical terminals and a missing bond at the pump motor?

• AReduced heater output
• BIncreased shock risk to swimmers and equipment damage from stray current
• CLoss of cyanuric acid
• DOverflow from the skimmer

What is the recommended pH range for residential pool water according to widely cited industry guidance?

• A5.0 to 6.0
• B6.5 to 7.0
• C7.4 to 7.6
• D8.5 to 9.0

What is the recommended total alkalinity range for pool water?

• A10-30 ppm
• B80-120 ppm
• C300-500 ppm
• D800-1,000 ppm

Which statement BEST describes 'free chlorine' vs 'combined chlorine' in pool water?

• AFree chlorine is the chlorine that has reacted with ammonia/nitrogen contaminants; combin…
• BFree chlorine is the sanitizing chlorine available to disinfect; combined chlorine is chl…
• CFree chlorine and combined chlorine are the same thing
• DCombined chlorine is more effective than free chlorine

Many health departments require combined chlorine in public pools to be kept BELOW what level?

• A0.4 ppm
• B5 ppm
• C20 ppm
• D100 ppm

Cyanuric acid (CYA) is used in outdoor pools to:

• AIncrease pH
• BStabilize free chlorine against breakdown by ultraviolet sunlight
• CRemove combined chlorine
• DSoften pool water

What is a typical recommended cyanuric acid (CYA) range for an outdoor residential pool?

• A0 ppm (no CYA)
• B30-50 ppm
• C150-200 ppm
• D500-1,000 ppm

ORP (oxidation-reduction potential) sensors are used at many commercial pools to:

• AMeasure pH
• BProvide a real-time millivolt reading correlated to sanitizing strength of the water
• CMeasure cyanuric acid
• DDetect calcium hardness

What is the typical recommended calcium hardness range for plaster (concrete) pools to prevent both etching and scaling?

• A0-50 ppm
• B200-400 ppm
• C1,000-2,000 ppm
• D5,000+ ppm

What is the practical purpose of 'shocking' or 'breakpoint chlorination' of a pool?

• ALower the pH rapidly
• BRaise free chlorine high enough to oxidize chloramines and organic contaminants, returnin…
• CReplace cyanuric acid
• DTest calcium hardness

An inspector tests pool water and finds: free chlorine 0.5 ppm, combined chlorine 1.5 ppm, pH 8.2, alkalinity 200 ppm. Which finding represents the GREATEST sanitation concern?

• ALow free chlorine combined with high combined chlorine and high pH indicates ineffective…
• BAlkalinity 200 ppm is the immediate health concern
• CThe water is perfectly balanced
• DpH 8.2 by itself would prevent algae

What is the function of muriatic acid (hydrochloric acid) in pool water chemistry adjustment?

• AIncrease pH
• BLower pH and/or total alkalinity
• CRemove cyanuric acid
• DIncrease calcium hardness

Which test result combination is MOST consistent with 'aggressive' (etching) water in a plaster pool?

• ApH 8.5, calcium hardness 500 ppm, alkalinity 200 ppm
• BpH 6.8, calcium hardness 80 ppm, alkalinity 40 ppm
• CpH 7.5, calcium hardness 300 ppm, alkalinity 100 ppm
• DpH 8.0, calcium hardness 250 ppm, alkalinity 120 ppm

Pool chlorine is MOST effective as a sanitizer at which approximate pH?

• ABelow 6.5
• BAround 7.4-7.6
• CAround 8.5
• DAbove 9.5

Per widely adopted IRC/ISPSC residential pool barrier provisions, the MINIMUM height of a pool barrier (fence) measured from grade on the outside of the barrier is:

• A36 inches
• B42 inches
• C48 inches
• D60 inches

Residential pool pedestrian gates serving the barrier must be:

• ASelf-closing and self-latching, opening outward away from the pool
• BPush-pull, opening toward the pool for child convenience
• CLocked only when the pool is in use
• DHeld open with a kick stop

When a pool barrier's gate latch release is mounted on the POOL side of the gate, the latch must be at least how far below the top of the gate?

• A1 inch below the top
• B3 inches below the top
• C6 inches above the top
• DThere is no requirement when on the pool side

When the barrier gate's latch release mechanism is on the NON-pool (outside) side, what is the minimum height above the surface below?

• A30 inches
• B42 inches
• C54 inches
• D72 inches

What is the maximum allowable opening size in a pool barrier through which a passable sphere should NOT pass?

• A1/2 inch sphere
• B2 inch sphere
• C4 inch sphere
• D9 inch sphere

When a dwelling wall is part of the pool barrier (no separate fence on that side), what is the typical code requirement to limit unsupervised access from the house to the pool?

• ANo requirement; dwelling walls always satisfy the barrier
• BDoors leading to the pool must be equipped with an alarm or a powered safety cover meetin…
• CAll exterior windows must be permanently sealed
• DOnly a guard dog is required