CALIFORNIA D2 EXAM PRACTICE QUESTIONS
WITH CORRECT ANSWERS 2025
When a water sample indicates a positive number on the Langelier Index this usually indicates what? -
CORRECT ANSWER -Scale Forming Water
A class "A: type of fire involves - CORRECT ANSWER -Wood, paper, and textile
When certain organic precursors and chlorine combine together in water during disinfection, by-
products can be formed. These organic by products are called: - CORRECT ANSWER -
Total Trihalomethanes
Which of the following is responsible for rotten egg odor in water? - CORRECT ANSWER -H2S
What type of water sample must be collected anytime water system pressure drops below 5 psi? -
CORRECT ANSWER -Special bac-t
The minimum water system pressure requirement for fire flow is: - CORRECT ANSWER -20 psig
When marking lines for utilities colors are used to identify the type of utility, which color is used to iden
tify communications lines? - CORRECT ANSWER -Orange
Minimum spoil set-back from an open trench is: - CORRECT ANSWER -2 feet or more
California DPHS has a maximum residual disinfection level (MRDL) for drinking water at: -
CORRECT ANSWER -4 ppm free available chlorine and 4 ppm total chlorine residual
A rest stop located along an interstate highway with a well supplying water for public use would be class
ified as a: - CORRECT ANSWER -transient-non community water system
California DPHS has a minimum detectable residual level for drinking water at: - CORRECT ANSWER -
0.2 ppm free available chlorine and 0.2 ppm total chlorine residual
, Which of the following chemical compound is used as a primary disinfectant at the well head? -
CORRECT ANSWER -Sodium Hypochlorite
Which type of tank has a height much greater than it's diameter? - CORRECT ANSWER -Stand Pipe
The occurrence of a fecal coliform (E.coli) and a total coliform in consecutive samples from the same sa
mple site constitutes: - CORRECT ANSWER -Tier 1, acute MCLRviolation and requires public notification
ARwater sample pH indicates 5.5, this is - CORRECT ANSWER -Acidic
The name of the valve used to connect a 3/4 inch up to a 2 inch service to a water main is called: -
CORRECT ANSWER -Corporation Valve
An indicator organism commonly used to determine drinking water contamination is: -
CORRECT ANSWER -Total Coliform Bacteria
Which of the following is a health related primary acute toxic contaminant thatRcan cause blue-
baby syndrome? - CORRECT ANSWER -Nitrate
CAL-
OSHA requires protective system be used anytime the trench depth is or more -
CORRECT ANSWER -5 Feet
Sodium thiosulfate is added to a microbiological sample bottle in order to: - CORRECT ANSWER -
Remove any chlorine residual present
Before collecting a routine coliform bacteriological compliance sample the operator should always meas
ure and record the: - CORRECT ANSWER -Chlorine residual
Which of the following is a health related primary acute toxic contaminant? - CORRECT ANSWER -
Nitrate
WITH CORRECT ANSWERS 2025
When a water sample indicates a positive number on the Langelier Index this usually indicates what? -
CORRECT ANSWER -Scale Forming Water
A class "A: type of fire involves - CORRECT ANSWER -Wood, paper, and textile
When certain organic precursors and chlorine combine together in water during disinfection, by-
products can be formed. These organic by products are called: - CORRECT ANSWER -
Total Trihalomethanes
Which of the following is responsible for rotten egg odor in water? - CORRECT ANSWER -H2S
What type of water sample must be collected anytime water system pressure drops below 5 psi? -
CORRECT ANSWER -Special bac-t
The minimum water system pressure requirement for fire flow is: - CORRECT ANSWER -20 psig
When marking lines for utilities colors are used to identify the type of utility, which color is used to iden
tify communications lines? - CORRECT ANSWER -Orange
Minimum spoil set-back from an open trench is: - CORRECT ANSWER -2 feet or more
California DPHS has a maximum residual disinfection level (MRDL) for drinking water at: -
CORRECT ANSWER -4 ppm free available chlorine and 4 ppm total chlorine residual
A rest stop located along an interstate highway with a well supplying water for public use would be class
ified as a: - CORRECT ANSWER -transient-non community water system
California DPHS has a minimum detectable residual level for drinking water at: - CORRECT ANSWER -
0.2 ppm free available chlorine and 0.2 ppm total chlorine residual
, Which of the following chemical compound is used as a primary disinfectant at the well head? -
CORRECT ANSWER -Sodium Hypochlorite
Which type of tank has a height much greater than it's diameter? - CORRECT ANSWER -Stand Pipe
The occurrence of a fecal coliform (E.coli) and a total coliform in consecutive samples from the same sa
mple site constitutes: - CORRECT ANSWER -Tier 1, acute MCLRviolation and requires public notification
ARwater sample pH indicates 5.5, this is - CORRECT ANSWER -Acidic
The name of the valve used to connect a 3/4 inch up to a 2 inch service to a water main is called: -
CORRECT ANSWER -Corporation Valve
An indicator organism commonly used to determine drinking water contamination is: -
CORRECT ANSWER -Total Coliform Bacteria
Which of the following is a health related primary acute toxic contaminant thatRcan cause blue-
baby syndrome? - CORRECT ANSWER -Nitrate
CAL-
OSHA requires protective system be used anytime the trench depth is or more -
CORRECT ANSWER -5 Feet
Sodium thiosulfate is added to a microbiological sample bottle in order to: - CORRECT ANSWER -
Remove any chlorine residual present
Before collecting a routine coliform bacteriological compliance sample the operator should always meas
ure and record the: - CORRECT ANSWER -Chlorine residual
Which of the following is a health related primary acute toxic contaminant? - CORRECT ANSWER -
Nitrate
