C475 EXAMINATION SET 2026 SOLVED
QUESTIONS GRADED A+
● What is installed when poor subgrade or groundwater is present?
Answer: Drain backfill section, up to 18 inches max depth, installed and
compacted as directed by the engineer.
● What plate must be referenced in addition to Plate 20? Answer: Plate
19 (Trench Section Backfill Notes).
● What is required when crossing an existing non-potable water main?
Answer: A steel casing around the potable line with required clearances.
● What type of fittings are required at the casing ends? Answer:
Restrained fittings.
● How does Plate 22 differ from Plate 21? Answer: Plate 22 applies
when the non-potable line is new, not existing.
● Is casing still required for new non-potable lines? Answer: Yes — steel
casing is required.
● What material is required for water main casing? Answer: Steel
casing, sized per casing table.
, ● What must be installed between the carrier pipe and casing? Answer:
Pipe spacers.
● What seals are required at casing ends? Answer: End seals to prevent
debris and water intrusion.
● When are anchor blocks required instead of thrust blocks? Answer:
For in-line reducers or gate valves where thrust restraint is needed.
● What controls anchor block sizing? Answer: Pipe diameter and fitting
type, per plate details.
● Where are thrust blocks required? Answer: At bends, tees, dead ends,
and hydrant shoes.
● What must thrust blocks bear against? Answer: Undisturbed native
soil.
● When is chlorination required? Answer: After new main installation,
repair, or extension.
● What must occur before placing the main into service? Answer:
Disinfection, flushing, and bacteriological testing.
QUESTIONS GRADED A+
● What is installed when poor subgrade or groundwater is present?
Answer: Drain backfill section, up to 18 inches max depth, installed and
compacted as directed by the engineer.
● What plate must be referenced in addition to Plate 20? Answer: Plate
19 (Trench Section Backfill Notes).
● What is required when crossing an existing non-potable water main?
Answer: A steel casing around the potable line with required clearances.
● What type of fittings are required at the casing ends? Answer:
Restrained fittings.
● How does Plate 22 differ from Plate 21? Answer: Plate 22 applies
when the non-potable line is new, not existing.
● Is casing still required for new non-potable lines? Answer: Yes — steel
casing is required.
● What material is required for water main casing? Answer: Steel
casing, sized per casing table.
, ● What must be installed between the carrier pipe and casing? Answer:
Pipe spacers.
● What seals are required at casing ends? Answer: End seals to prevent
debris and water intrusion.
● When are anchor blocks required instead of thrust blocks? Answer:
For in-line reducers or gate valves where thrust restraint is needed.
● What controls anchor block sizing? Answer: Pipe diameter and fitting
type, per plate details.
● Where are thrust blocks required? Answer: At bends, tees, dead ends,
and hydrant shoes.
● What must thrust blocks bear against? Answer: Undisturbed native
soil.
● When is chlorination required? Answer: After new main installation,
repair, or extension.
● What must occur before placing the main into service? Answer:
Disinfection, flushing, and bacteriological testing.
