WATER OPERATOR CLASS D EXAMINATION STUDY SHEET 2026 VERIFIED QUESTION– ANSWER COLLECTION

WATER OPERATOR CLASS D EXAMINATION
STUDY SHEET 2026 VERIFIED QUESTION–
ANSWER COLLECTION

◉ Backwashing should expand the filter bed by ___ percent.
A)5 to 10
B)15 to 20
C)25 to 30
D)30 to 50.
Answer: D


◉ A common filter problem is ___, prevented by proper backwashing.
A)ice
B)mud balls
C)detention time
D)coagulation.
Answer: B


◉ Chemicals used disinfection are chloramine, chlorine, chlorine
dioxide, and ___.
A)ferrous sulfate

,B)copper sulfate
C)activated carbon
D)ozone.
Answer: D


◉ T/F: Disinfection destroys disease-causing microorganisms called
pathogens..
Answer: True


◉ T/F: Disinfection destroys pathogens without sterilizing the
water..
Answer: True


◉ T/F: Waterborne pathogens live and grow in the intestines of
infected people..
Answer: True


◉ T/F: Infected fecal matter entering a water supply transmits
pathogens to healthy people..
Answer: True


◉ T/F: Some disease transmitted by unsafe water include typhoid,
dysentery, cholera, measles, polio, cryptosporidiosis..

, Answer: False (True if list did not include measles)


◉ T/F: Each water sample is tested for all waterborne diseases..
Answer: False


◉ T/F: Water samples are tested for microorganisms that indicate
fecal contamination..
Answer: True


◉ T/F: The total coliform group of viruses are the indicators of fecal
contamination..
Answer: False


◉ T/F: Fecal coliform live in the intestines of humans and warm-
blooded animals..
Answer: True


◉ T/F: The presence of fecal coliform in a water sample indicates
intestinal waste is in the sample, but there is no risk of disease.
Answer: False (no risk is questionable)


◉ T/F: The number of water taps served by the system determines
the minimum number of bacteriological samples..