Page 1 of 51
07 June 2026
Florida Class C Water Treatment Operator Exam 2026/2027
Prep Test Bank with 600 Most Recent Questions and
Correct Verified Answers/ FL Class C Water Operator Test
Latest (Brand New!)
why is nitric acid added to samples collected for iron and manganese analysis? - correct
answerlowers PH and keeps metals in solution
what is the longest running production sports car? - correct answer-corvette (1954)
a filter has a sudden increase in head loss. Media surface sealing is suspected. what action should
be taken? - correct answer-evaluate plant process, jar test if needed
when chlorine is added to water, it is a more efficient disinfectant when the PH is lower and a
greater percentage of ______ is present. - correct answer-HOCL
the term flash mix is associated with which of the following processes? - correct answercoagulation
disinfection is best accomplished when what conditions exist? - correct answer-high
concentration and long contact time
you are working with a solution with a 15% chemical strength. How many pounds of chemical are
in this solution? - correct answer-1.25
the plant flow is 7.5 MGD. The treatment unit is 70' long, 20' wide, and 10' deep. what is the
detention time in minutes? - correct answer-34 minutes
five pounds of HTH are added to 100 gallons of water for disinfection. 80 gal. of the solution were
used. How many pounds of chlorine were actually used? - correct answer-2.6
what NBA player was a Defensive Player of the Year and the league leader in scoring in the same
season? - correct answer-MJ
, Page 2 of 51
07 June 2026
what NFL running back has the most rushing yards all time? - correct answer-Emmitt Smith?
taste and odor problems required super chlorination in plant. how would you dechlorinate before
sending the water to distribution? - correct answer-GAC
which of these terms best describes electrolysis? - correct answer-stray current
convert 250 mg/l of total hardness to grains per gallon - correct answer-15
convert 35 gpg to mg/l of total hardness - correct answer-599
the pressure gauge on the chlorine feed reads 90s and the injector gauge reads 10s. The chlorine
residual keeps dropping. what is most likely the cause? - correct answer-restriction in supply line
what color is concrete? - correct answer-grey
when installing a pipe fitting that will change direction of flow. what is the proper installation
method? - correct answer-thrust block
how long must water plant operation records be kept on site? - correct answer-10 years
what is usually indicated when at sample point "A" in a water main a high DO reading is obtained,
and at sample point "B" downstream, the DO reading is substantially lower? - correct
answercorrosion
when is THM formation more likely to occur? - correct answer-spring and fall
with what material is hydrochloric acid highly reactive? - correct answer-metals
sand drying beds are similar in construction to ? - correct answer-gravity sand filters
, Page 3 of 51
07 June 2026
calculate the langlier index where the PH = 8.8, and the PHs is 8.3 - correct answer-+0.5
a positive langlier index is _______. - correct answer-scale forming
what do we call a detailed description of all underground features discovered during well drilling? -
correct answer-geological log
what information is need to calculate the PHs for the langlier index? - correct answer-temp, TDS,
Alkalinity, Calcium hardness
what process is commonly used to remove volatile organics from water? - correct
answerpolyphosphates
how often must a water system test for radionuclides? - correct answer-3 yrs
calculate the amount of water needed to backwash a 360 sq ft dilter at 9000 gpm. the backwash
duration is 8 minutes. - correct answer-72,000 gal
in January a 6 ppm Cl2 dosage produced a 2.0 ppm residual. In July an 8 ppm dosage produced a 1.5
ppm residual. what is most likely the cause for the lower chlorine residual? - correct
answerincrease in water temperature
why is recarbonation necessary when lime softening is used to reduce excessive hydroxide
hardness? - correct answer-reduce the scale forming tendencies of the supersaturated H2O
In hot water systems, scaling is a problem because _________ is less soluble in hot H2O than it is in
cold H2O. - correct answer-calcium carbonate
what is the primary purpose of filters in a WTP? - correct answer-lower turbidity
a WTP meets or exceeds all treatment parameters. It has started to receive customer complaints
concerning red water in the distribution system. Polyphosphate is being used in the treatment
, Page 4 of 51
07 June 2026
process. what is most likely causing the red water? - correct answer-polyphosphate reverted to
orthophosphate
a well pump is rated at 6000 gpm at 85% efficiency. the well is 15' long, 12' wide, and 10' deep. if the
pump takes 10 minutes to lower the well 5 feet, does it pump higher or lower than rated? - correct
answer-73 gpm, higher
what will happen if the recirculation rate for a solid contact unit is too high? - correct
answeroverflow of slurry to filter
if a water sample tests positive for coliform, what action must be taken by the water system? -
correct answer-repeat sample 24 hours after notification
Many samples for MCL compliance are taken in the distribution system. what sample is taken where
the water enters the distribution system? - correct answer-turbidity
when taking a hardness test, the titration should be completed within 5 min. An inhibitor reagent
should be used when metal ion interference causes an indistinct end point, and _________. -
correct answer-a sample volume should be selected which requires less than 15 ml of EDTA titrant.
to control THM formation, alternate disinfectants are used including ozone, chlorine dioxide, and
_______. - correct answer-chloramines.
to insure membrane longevity and slow down hydrolysis, RO plants add _____? - correct
answeracid
the recovery rate of a membrane softening plant is limited by what two factors? - correct
answerdesired product h2o quality and mineral content
media loss is caused by high backwash rate and air bubbles caused by? - correct answer-air binding
when alum dosage is decreased, lime dosage may? - correct answer-decrease
07 June 2026
Florida Class C Water Treatment Operator Exam 2026/2027
Prep Test Bank with 600 Most Recent Questions and
Correct Verified Answers/ FL Class C Water Operator Test
Latest (Brand New!)
why is nitric acid added to samples collected for iron and manganese analysis? - correct
answerlowers PH and keeps metals in solution
what is the longest running production sports car? - correct answer-corvette (1954)
a filter has a sudden increase in head loss. Media surface sealing is suspected. what action should
be taken? - correct answer-evaluate plant process, jar test if needed
when chlorine is added to water, it is a more efficient disinfectant when the PH is lower and a
greater percentage of ______ is present. - correct answer-HOCL
the term flash mix is associated with which of the following processes? - correct answercoagulation
disinfection is best accomplished when what conditions exist? - correct answer-high
concentration and long contact time
you are working with a solution with a 15% chemical strength. How many pounds of chemical are
in this solution? - correct answer-1.25
the plant flow is 7.5 MGD. The treatment unit is 70' long, 20' wide, and 10' deep. what is the
detention time in minutes? - correct answer-34 minutes
five pounds of HTH are added to 100 gallons of water for disinfection. 80 gal. of the solution were
used. How many pounds of chlorine were actually used? - correct answer-2.6
what NBA player was a Defensive Player of the Year and the league leader in scoring in the same
season? - correct answer-MJ
, Page 2 of 51
07 June 2026
what NFL running back has the most rushing yards all time? - correct answer-Emmitt Smith?
taste and odor problems required super chlorination in plant. how would you dechlorinate before
sending the water to distribution? - correct answer-GAC
which of these terms best describes electrolysis? - correct answer-stray current
convert 250 mg/l of total hardness to grains per gallon - correct answer-15
convert 35 gpg to mg/l of total hardness - correct answer-599
the pressure gauge on the chlorine feed reads 90s and the injector gauge reads 10s. The chlorine
residual keeps dropping. what is most likely the cause? - correct answer-restriction in supply line
what color is concrete? - correct answer-grey
when installing a pipe fitting that will change direction of flow. what is the proper installation
method? - correct answer-thrust block
how long must water plant operation records be kept on site? - correct answer-10 years
what is usually indicated when at sample point "A" in a water main a high DO reading is obtained,
and at sample point "B" downstream, the DO reading is substantially lower? - correct
answercorrosion
when is THM formation more likely to occur? - correct answer-spring and fall
with what material is hydrochloric acid highly reactive? - correct answer-metals
sand drying beds are similar in construction to ? - correct answer-gravity sand filters
, Page 3 of 51
07 June 2026
calculate the langlier index where the PH = 8.8, and the PHs is 8.3 - correct answer-+0.5
a positive langlier index is _______. - correct answer-scale forming
what do we call a detailed description of all underground features discovered during well drilling? -
correct answer-geological log
what information is need to calculate the PHs for the langlier index? - correct answer-temp, TDS,
Alkalinity, Calcium hardness
what process is commonly used to remove volatile organics from water? - correct
answerpolyphosphates
how often must a water system test for radionuclides? - correct answer-3 yrs
calculate the amount of water needed to backwash a 360 sq ft dilter at 9000 gpm. the backwash
duration is 8 minutes. - correct answer-72,000 gal
in January a 6 ppm Cl2 dosage produced a 2.0 ppm residual. In July an 8 ppm dosage produced a 1.5
ppm residual. what is most likely the cause for the lower chlorine residual? - correct
answerincrease in water temperature
why is recarbonation necessary when lime softening is used to reduce excessive hydroxide
hardness? - correct answer-reduce the scale forming tendencies of the supersaturated H2O
In hot water systems, scaling is a problem because _________ is less soluble in hot H2O than it is in
cold H2O. - correct answer-calcium carbonate
what is the primary purpose of filters in a WTP? - correct answer-lower turbidity
a WTP meets or exceeds all treatment parameters. It has started to receive customer complaints
concerning red water in the distribution system. Polyphosphate is being used in the treatment
, Page 4 of 51
07 June 2026
process. what is most likely causing the red water? - correct answer-polyphosphate reverted to
orthophosphate
a well pump is rated at 6000 gpm at 85% efficiency. the well is 15' long, 12' wide, and 10' deep. if the
pump takes 10 minutes to lower the well 5 feet, does it pump higher or lower than rated? - correct
answer-73 gpm, higher
what will happen if the recirculation rate for a solid contact unit is too high? - correct
answeroverflow of slurry to filter
if a water sample tests positive for coliform, what action must be taken by the water system? -
correct answer-repeat sample 24 hours after notification
Many samples for MCL compliance are taken in the distribution system. what sample is taken where
the water enters the distribution system? - correct answer-turbidity
when taking a hardness test, the titration should be completed within 5 min. An inhibitor reagent
should be used when metal ion interference causes an indistinct end point, and _________. -
correct answer-a sample volume should be selected which requires less than 15 ml of EDTA titrant.
to control THM formation, alternate disinfectants are used including ozone, chlorine dioxide, and
_______. - correct answer-chloramines.
to insure membrane longevity and slow down hydrolysis, RO plants add _____? - correct
answeracid
the recovery rate of a membrane softening plant is limited by what two factors? - correct
answerdesired product h2o quality and mineral content
media loss is caused by high backwash rate and air bubbles caused by? - correct answer-air binding
when alum dosage is decreased, lime dosage may? - correct answer-decrease
