Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
1.
Who is authorized to remove a lock and tag placed on a piece of equipment to
isolate it for maintenance?
A) The plant supervisor
B) Any certified operator
C) The maintenance manager
D) Only the person who placed the lock and tag Correct Answer:
2.
In addition to an emergency residual pressure of 20 psi, what is the minimum
normal operating pressure a public water supply system should maintain?
A) 20 psi
B) 25 psi
C) 35 psi Correct Answer:
D) 50 psi
3.
What is the minimum distance separating installed water mains from any sewer
lines or other possible contaminated lines?
A) 3 feet
B) 6 feet
C) 9 feet Correct Answer:
Page 1 of 42
,Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
D) 12 feet
4.
What is the minimum distance required to separate grazing livestock and septic
tanks from a public well?
A) 25 feet
B) 50 feet Correct Answer:
C) 100 feet
D) 500 feet
5.
What color does the sample turn when the DPD reagent is added to water
containing chlorine?
A) Blue
B) Green
C) Red Correct Answer:
D) Yellow
6.
A system operates at a flow rate of 2.2 MGD. A chlorine dose of 10 mg/L is
required to maintain a disinfectant residual of 0.4 mg/L. Calculate the daily
chlorine demand in pounds.
Page 2 of 42
,Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
A) 88 lbs
B) 176 lbs Correct Answer:
C) 264 lbs
D) 350 lbs
7.
A tank with 1 foot of water above a pressure gauge at the bottom will register a
reading of:
A) 0.433 psi Correct Answer:
B) 1 psi
C) 0.25 psi
D) 0.1 psi
8.
Pipe and fittings used in public water systems may not contain more than ____%
lead or solder and flux may not contain more than ____% lead.
A) 1.0%, 0.5%
B) 0.25%, 0.2% Correct Answer:
C) 0.5%, 0.5%
D) 0.3%, 0.1%
9.
Page 3 of 42
, Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
Chlorine tablets (Calcium hypochlorite) should not come in contact with
________ based products due to violent reaction.
A) Alcohol
B) Petroleum Correct Answer:
C) Ammonia
D) Bleach
10.
The condition caused by high nitrate levels in drinking water that affects young
children is called:
A) Typhoid fever
B) Methemoglobinemia ("Blue Baby Syndrome") Correct Answer:
C) Dysentery
D) E. coli infection
11.
How much does one gallon of water weigh?
A) 7.48 lbs
B) 8.34 lbs Correct Answer:
C) 9.0 lbs
D) 8.00 lbs
12.
Page 4 of 42
Verified Q&A (Latest Certified Edition).
1.
Who is authorized to remove a lock and tag placed on a piece of equipment to
isolate it for maintenance?
A) The plant supervisor
B) Any certified operator
C) The maintenance manager
D) Only the person who placed the lock and tag Correct Answer:
2.
In addition to an emergency residual pressure of 20 psi, what is the minimum
normal operating pressure a public water supply system should maintain?
A) 20 psi
B) 25 psi
C) 35 psi Correct Answer:
D) 50 psi
3.
What is the minimum distance separating installed water mains from any sewer
lines or other possible contaminated lines?
A) 3 feet
B) 6 feet
C) 9 feet Correct Answer:
Page 1 of 42
,Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
D) 12 feet
4.
What is the minimum distance required to separate grazing livestock and septic
tanks from a public well?
A) 25 feet
B) 50 feet Correct Answer:
C) 100 feet
D) 500 feet
5.
What color does the sample turn when the DPD reagent is added to water
containing chlorine?
A) Blue
B) Green
C) Red Correct Answer:
D) Yellow
6.
A system operates at a flow rate of 2.2 MGD. A chlorine dose of 10 mg/L is
required to maintain a disinfectant residual of 0.4 mg/L. Calculate the daily
chlorine demand in pounds.
Page 2 of 42
,Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
A) 88 lbs
B) 176 lbs Correct Answer:
C) 264 lbs
D) 350 lbs
7.
A tank with 1 foot of water above a pressure gauge at the bottom will register a
reading of:
A) 0.433 psi Correct Answer:
B) 1 psi
C) 0.25 psi
D) 0.1 psi
8.
Pipe and fittings used in public water systems may not contain more than ____%
lead or solder and flux may not contain more than ____% lead.
A) 1.0%, 0.5%
B) 0.25%, 0.2% Correct Answer:
C) 0.5%, 0.5%
D) 0.3%, 0.1%
9.
Page 3 of 42
, Texas Class D Water License Exam – 150
Verified Q&A (Latest Certified Edition).
Chlorine tablets (Calcium hypochlorite) should not come in contact with
________ based products due to violent reaction.
A) Alcohol
B) Petroleum Correct Answer:
C) Ammonia
D) Bleach
10.
The condition caused by high nitrate levels in drinking water that affects young
children is called:
A) Typhoid fever
B) Methemoglobinemia ("Blue Baby Syndrome") Correct Answer:
C) Dysentery
D) E. coli infection
11.
How much does one gallon of water weigh?
A) 7.48 lbs
B) 8.34 lbs Correct Answer:
C) 9.0 lbs
D) 8.00 lbs
12.
Page 4 of 42
