Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
1. The most important responsibility of Water Utility personnel is to - Correct
Answer: Provide water that is safe for all purposes
2. A Class D water operator license/certificate is only valid for this type of
system. - Correct Answer: Ground water systems with less than 250
connections
3. This type of meter is normally used for low flows - Correct Answer:
Positive Displacement Meter
4. Pumping rates are usually expressed as: - Correct Answer: GPM
(gallons per minute)
5. Potable water is free of - Correct Answer: disease causing organisms
6. When an MCL is exceeded what is required by the Federal Safe Drinking
Water Act? - Correct Answer: public notification
7. When an MCL is exceeded public notification is required by - Correct
Answer: the Federal Safe Drinking Water Act
8. public notification is required by the Federal Safe Drinking Water Act when -
Correct Answer: an MCL is exceeded
Page 1 of 108
,Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
9. Flocculation helps to - Correct Answer: remove impurities in the
water
10.The Safe Drinking Water Act does this - Correct Answer: Sets MCLs for
drinking water
11.Groundwater occurs below the earth's surface in water-bearing formations
called: - Correct Answer: aquifers
12.Sewers must be kept at least this far from a well - Correct Answer: 50
feet
13.Watershed - Correct Answer: The area of runoff of a surface water
source
14.A water system is required to have ground storage if - Correct Answer:
they have 50 or more connections
15.pressure tank storage - Correct Answer: hydropneumatic tanks;
cylindrical and horizontal to the ground; Air mechanically compressed against
the water surface provides pressure
16.A water system without ground storage must have a pressure tank capacity
of - Correct Answer: 50 gallons per connection
Page 2 of 108
,Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
17.A water system with ground storage is allowed to have - Correct Answer:
a pressure tank capacity of 20 gallons per connection, or elevated
storage.
18.The exterior and interior of ground, elevated, standpipe and pressure tanks
must be inspected how often? - Correct Answer: yearly
19.The exterior and interior of ground, elevated, standpipe and pressure tanks
must be inspected by who? - Correct Answer: water system personnel
or a contracted service
20.storage tank inspections must be - Correct Answer: documented
21.storage tank inspection documentation must be kept for how long? - Correct
Answer: at least 5 years
22.The exterior and interior coating of storage tanks must be inspected for -
Correct Answer: corrosion protection
23.The interior of storage tanks must meet these specifications - Correct
Answer: AWWA
24.Adequate water pressure in the system prevents this - Correct Answer:
contaminated water from being drawn into the system.
Page 3 of 108
, Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
25.Lead limits for pipe and fittings - Correct Answer: not more than 8%
lead
26.Lead limits for solders and flux - Correct Answer: not more than 0.2%
lead
27.Water mains must be no closer than this, in all directions, from sewers and
manholes. - Correct Answer: 9 feet
28.Distances from water mains are measured from - Correct Answer: the
outside surface of the pipe
29.Parallel water and sewer lines must be laid - Correct Answer: in
separate ditches
30.An important part of public relations is to - Correct Answer: provide
courteous treatment to customers
31.The process of nature recycling water is called - Correct Answer: the
hydrological cycle
32.The Parts of the hydrologic cycle - Correct Answer: Transpiration;
precipitation; evaporation; infiltration (percolation); condensation
33.The presence of these in a system should cause concern - Correct Answer:
indicator organisms
Page 4 of 108
– Complete Study Guide with Answers.
1. The most important responsibility of Water Utility personnel is to - Correct
Answer: Provide water that is safe for all purposes
2. A Class D water operator license/certificate is only valid for this type of
system. - Correct Answer: Ground water systems with less than 250
connections
3. This type of meter is normally used for low flows - Correct Answer:
Positive Displacement Meter
4. Pumping rates are usually expressed as: - Correct Answer: GPM
(gallons per minute)
5. Potable water is free of - Correct Answer: disease causing organisms
6. When an MCL is exceeded what is required by the Federal Safe Drinking
Water Act? - Correct Answer: public notification
7. When an MCL is exceeded public notification is required by - Correct
Answer: the Federal Safe Drinking Water Act
8. public notification is required by the Federal Safe Drinking Water Act when -
Correct Answer: an MCL is exceeded
Page 1 of 108
,Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
9. Flocculation helps to - Correct Answer: remove impurities in the
water
10.The Safe Drinking Water Act does this - Correct Answer: Sets MCLs for
drinking water
11.Groundwater occurs below the earth's surface in water-bearing formations
called: - Correct Answer: aquifers
12.Sewers must be kept at least this far from a well - Correct Answer: 50
feet
13.Watershed - Correct Answer: The area of runoff of a surface water
source
14.A water system is required to have ground storage if - Correct Answer:
they have 50 or more connections
15.pressure tank storage - Correct Answer: hydropneumatic tanks;
cylindrical and horizontal to the ground; Air mechanically compressed against
the water surface provides pressure
16.A water system without ground storage must have a pressure tank capacity
of - Correct Answer: 50 gallons per connection
Page 2 of 108
,Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
17.A water system with ground storage is allowed to have - Correct Answer:
a pressure tank capacity of 20 gallons per connection, or elevated
storage.
18.The exterior and interior of ground, elevated, standpipe and pressure tanks
must be inspected how often? - Correct Answer: yearly
19.The exterior and interior of ground, elevated, standpipe and pressure tanks
must be inspected by who? - Correct Answer: water system personnel
or a contracted service
20.storage tank inspections must be - Correct Answer: documented
21.storage tank inspection documentation must be kept for how long? - Correct
Answer: at least 5 years
22.The exterior and interior coating of storage tanks must be inspected for -
Correct Answer: corrosion protection
23.The interior of storage tanks must meet these specifications - Correct
Answer: AWWA
24.Adequate water pressure in the system prevents this - Correct Answer:
contaminated water from being drawn into the system.
Page 3 of 108
, Water Operator Class D Final Exam 2026 Entry
– Complete Study Guide with Answers.
25.Lead limits for pipe and fittings - Correct Answer: not more than 8%
lead
26.Lead limits for solders and flux - Correct Answer: not more than 0.2%
lead
27.Water mains must be no closer than this, in all directions, from sewers and
manholes. - Correct Answer: 9 feet
28.Distances from water mains are measured from - Correct Answer: the
outside surface of the pipe
29.Parallel water and sewer lines must be laid - Correct Answer: in
separate ditches
30.An important part of public relations is to - Correct Answer: provide
courteous treatment to customers
31.The process of nature recycling water is called - Correct Answer: the
hydrological cycle
32.The Parts of the hydrologic cycle - Correct Answer: Transpiration;
precipitation; evaporation; infiltration (percolation); condensation
33.The presence of these in a system should cause concern - Correct Answer:
indicator organisms
Page 4 of 108
