CALIFORNIA GRADE 1 WATER TREATMENT
OPERATOR CERTIFICATION EXAM 2026|ACTUAL 160
EXAM Qs&As|GRADED A+
What is one reason the chlorine demand would suddenly increase from 0.7 to
3.2 mg/L while treating raw water from a well?
A contaminant entered the aquifer
How will a decrease in water temperature affect the disinfecting action of
chlorine?
The disinfection is less effective
Examples of protozoa that must be removed from drinking water to protect
public health
Giardia and Cryptosporidium
How is water prevented from entering a gas chlorinator?
A check valve
,Of the following characteristics of raw water, the least likely to cause health
issues in consumers is ______?
physical
What is the never-ending transmission of water from the Earth into the
atmosphere and back again?
The Hydrologic Cycle
What fraction of the earth surface is covered with water?
Three-Quarters (3/4)
What is the process by which water becomes a gas and rises?
Evaporation
To deliberately form chloramines, a water supplier mixes chlorine gas with
_____?
Ammonia (ammonia + chlorine = chloramines)
,To remove a calcium scale deposit from the liquid head of a chemical feed
pump, remove it, then soak it in_____?
A weak solution of hydrochloric acid
Why is turbidity in drinking water is considered undesirable?
Because it necessitates extensive treatment and produces greater amounts of
sludge
What does HTH (high test hypochlorite), a dry white granular compound,
contain?
65 to 70% chlorine
What is a non-halogenic oxidizing chemical that may be substituted for pre-
chlorination to avoid formation of DBP's?
Potassium Permanganate
Which of the following forms the strongest disinfectant in solution?
Dichloramines
, The Colilert Method can detect the presence of both total and fecal coliforms
after how many hours of incubation?
18 to 24 hours
At what temperature is a fusible plug on a chlorine cylinder designed to melt
and release chlorine gas?
158 to 165°F
What alternative disinfectant is most commonly used to avoid the formation
of THM's (trihalomethanes) at larger water treatment plants?
Ozone (oxygen)
What are the nutrients in water taken up by algae during sunlight periods?
carbon, nitrates, and ammonia
What is the moisture passing from trees and other plants into the atmosphere
referred to as?
Evapotranspiration
OPERATOR CERTIFICATION EXAM 2026|ACTUAL 160
EXAM Qs&As|GRADED A+
What is one reason the chlorine demand would suddenly increase from 0.7 to
3.2 mg/L while treating raw water from a well?
A contaminant entered the aquifer
How will a decrease in water temperature affect the disinfecting action of
chlorine?
The disinfection is less effective
Examples of protozoa that must be removed from drinking water to protect
public health
Giardia and Cryptosporidium
How is water prevented from entering a gas chlorinator?
A check valve
,Of the following characteristics of raw water, the least likely to cause health
issues in consumers is ______?
physical
What is the never-ending transmission of water from the Earth into the
atmosphere and back again?
The Hydrologic Cycle
What fraction of the earth surface is covered with water?
Three-Quarters (3/4)
What is the process by which water becomes a gas and rises?
Evaporation
To deliberately form chloramines, a water supplier mixes chlorine gas with
_____?
Ammonia (ammonia + chlorine = chloramines)
,To remove a calcium scale deposit from the liquid head of a chemical feed
pump, remove it, then soak it in_____?
A weak solution of hydrochloric acid
Why is turbidity in drinking water is considered undesirable?
Because it necessitates extensive treatment and produces greater amounts of
sludge
What does HTH (high test hypochlorite), a dry white granular compound,
contain?
65 to 70% chlorine
What is a non-halogenic oxidizing chemical that may be substituted for pre-
chlorination to avoid formation of DBP's?
Potassium Permanganate
Which of the following forms the strongest disinfectant in solution?
Dichloramines
, The Colilert Method can detect the presence of both total and fecal coliforms
after how many hours of incubation?
18 to 24 hours
At what temperature is a fusible plug on a chlorine cylinder designed to melt
and release chlorine gas?
158 to 165°F
What alternative disinfectant is most commonly used to avoid the formation
of THM's (trihalomethanes) at larger water treatment plants?
Ozone (oxygen)
What are the nutrients in water taken up by algae during sunlight periods?
carbon, nitrates, and ammonia
What is the moisture passing from trees and other plants into the atmosphere
referred to as?
Evapotranspiration
