TEXAS CLASS D WATER DISTRIBUTION STUDY GUIDE
QUESTIONS WITH CORRECT ANSWERS 2025/2026
What is the name of the State Agency responsible for enforcing the Safe Drinking Water Act? -
CORRECT ANSWER -Texas Commission on Environmental Quality
what Minerals are associated with water hardness? - CORRECT ANSWER -Calcium and
magnesium
A public water system MUST at all times provide?
A. Adequate quantity of water
B. Adequate water pressure
c. Adequate disinfection
D. All of the above - CORRECT ANSWER -D. All of the above
A Source of groundwater would be? - CORRECT ANSWER -Aquifer
Fecal Coliform organisms sometimes found in water supplies are an indication that?
A. The water Supply is Contaminated
B. Harmful Bacteria may be present
C. Possible pathogenic organisms are in the water
D. The water is unsuitable for drinking
E. All of the above - CORRECT ANSWER -E. All of the above
A disease that may be spread by inadequately disinfected water is - CORRECT ANSWER -
Dysentery
, A Common Chemical used in the disinfection of a small water Supply is - CORRECT ANSWER -
Calcium hypochlorite
A public water Supply system should maintain a system residual pressure of 20 psi and a
minimum normal operating pressure of _____ - CORRECT ANSWER -35 psi
The amount of chlorine in mg/L that is used by reacting with iron, organics or bacteria is called -
CORRECT ANSWER -Demand
The MOST important treatment in water is - CORRECT ANSWER -Disinfection
Which of the following would be considered part(s) of a hypo-chlorinator system - CORRECT
ANSWER -Solution feed pump
According to state requirements all public water supply wells shall be provided with a raised
concrete sealing block screen vents and - CORRECT ANSWER -Flow Measuring Device
One method to determine the drawdown of a water well is - CORRECT ANSWER -An air line
The pH of the water indicates - CORRECT ANSWER -If it is more acid or base
Assuming you collect more than 1 bac-t sample monthly and your system receives notification
from the lab that one of the samples taken in the distribution system comes back positive your
repeat sample(s) must be taken within _____ hours and a total of _____ repeat samples must
be collected for each positive? - CORRECT ANSWER -24 hours and 3 repeat samples
Water that is considered neutral is expressed on the pH scale at - CORRECT ANSWER -7
QUESTIONS WITH CORRECT ANSWERS 2025/2026
What is the name of the State Agency responsible for enforcing the Safe Drinking Water Act? -
CORRECT ANSWER -Texas Commission on Environmental Quality
what Minerals are associated with water hardness? - CORRECT ANSWER -Calcium and
magnesium
A public water system MUST at all times provide?
A. Adequate quantity of water
B. Adequate water pressure
c. Adequate disinfection
D. All of the above - CORRECT ANSWER -D. All of the above
A Source of groundwater would be? - CORRECT ANSWER -Aquifer
Fecal Coliform organisms sometimes found in water supplies are an indication that?
A. The water Supply is Contaminated
B. Harmful Bacteria may be present
C. Possible pathogenic organisms are in the water
D. The water is unsuitable for drinking
E. All of the above - CORRECT ANSWER -E. All of the above
A disease that may be spread by inadequately disinfected water is - CORRECT ANSWER -
Dysentery
, A Common Chemical used in the disinfection of a small water Supply is - CORRECT ANSWER -
Calcium hypochlorite
A public water Supply system should maintain a system residual pressure of 20 psi and a
minimum normal operating pressure of _____ - CORRECT ANSWER -35 psi
The amount of chlorine in mg/L that is used by reacting with iron, organics or bacteria is called -
CORRECT ANSWER -Demand
The MOST important treatment in water is - CORRECT ANSWER -Disinfection
Which of the following would be considered part(s) of a hypo-chlorinator system - CORRECT
ANSWER -Solution feed pump
According to state requirements all public water supply wells shall be provided with a raised
concrete sealing block screen vents and - CORRECT ANSWER -Flow Measuring Device
One method to determine the drawdown of a water well is - CORRECT ANSWER -An air line
The pH of the water indicates - CORRECT ANSWER -If it is more acid or base
Assuming you collect more than 1 bac-t sample monthly and your system receives notification
from the lab that one of the samples taken in the distribution system comes back positive your
repeat sample(s) must be taken within _____ hours and a total of _____ repeat samples must
be collected for each positive? - CORRECT ANSWER -24 hours and 3 repeat samples
Water that is considered neutral is expressed on the pH scale at - CORRECT ANSWER -7
