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NYC DOB MASTER PLUMBER LICENSE
PRACTICE EXAM (CONTINUED)
QUESTIONS WITH VERIFIED ANSWERS &
COMPLETE RATIONALES
**41. What is the required size for a service pipe connection
that provides fire protection?**
A. 1 inch
B. 2 inches
C. 4 inches
D. 6 inches
**Correct answer:** C
**Rationale:** Per Title 15 RCNY § 20-02(k)(2), a curb valve
must be included on all water service connections that supply
fire protection systems. The minimum size for such fire service
connections is 4 inches.
---
**42. A Licensed Master Plumber is excavating a corporation
stop (tap) for removal. Upon excavation, the plumber discovers
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the service connection is supplied by two corporation stops.
What is the required action?**
A. Plug or destroy the additional corporation stop(s)
B. Notify the Department of Environmental Protection (DEP)
and wait for an inspector
C. Leave the additional corporation stop in place
D. Install a Siamese connection
**Correct answer:** A
**Rationale:** Per Title 15 RCNY § 20-02(g), the Licensed
Master Plumber making the excavation must plug or destroy
the additional corporation stops. The Licensed Master Plumber
is solely responsible for locating the corporation stops, and a
separate permit is required for each stop destroyed .
---
**43. What is the required minimum depth for a water service
pipe connection?**
A. 2 feet
B. 3 feet
C. 3.5 feet
D. 6 feet
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**Correct answer:** C
**Rationale:** Per Title 15 RCNY § 20-03(n), all service pipe
connections must be installed at a depth of at least 3½ feet, no
more than 6 feet below ground, unless a written waiver is
obtained from the Department. Where less than 3½ feet of
cover exists, the pipe must be insulated and protected .
---
**44. What is the minimum vertical distance required between a
water service pipe connection and any other sub-surface
structure?**
A. 3 inches
B. 6 inches
C. 12 inches
D. 18 inches
**Correct answer:** B
**Rationale:** Per Title 15 RCNY § 20-03(n), a service pipe
connection must not be laid within 6 inches of any other sub-
surface structure, conduit, or pipe, nor directly below and
parallel within 6 inches of any other sub-surface structure .
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---
**45. How must backfill be placed around and one foot over a
water service pipe connection?**
A. Clean earth, free of stones, carefully tamped and compacted
B. Any available soil from the excavation
C. Sand only, no compaction required
D. Gravel and crushed stone
**Correct answer:** A
**Rationale:** Per Title 15 RCNY § 20-03(q), backfill around
and one foot over a service pipe connection must be of clean
earth, free of stones, and must be carefully tamped and
compacted in accordance with NYC DOT Standard Highway
Specifications. The remainder of the backfill must be free of
stones larger than 3 inches in diameter .
---
**46. When must a house control valve be an OS&Y (Outside
Stem and Yoke) valve?**
A. For all domestic water service connections
NYC DOB MASTER PLUMBER LICENSE
PRACTICE EXAM (CONTINUED)
QUESTIONS WITH VERIFIED ANSWERS &
COMPLETE RATIONALES
**41. What is the required size for a service pipe connection
that provides fire protection?**
A. 1 inch
B. 2 inches
C. 4 inches
D. 6 inches
**Correct answer:** C
**Rationale:** Per Title 15 RCNY § 20-02(k)(2), a curb valve
must be included on all water service connections that supply
fire protection systems. The minimum size for such fire service
connections is 4 inches.
---
**42. A Licensed Master Plumber is excavating a corporation
stop (tap) for removal. Upon excavation, the plumber discovers
,2 | Page
the service connection is supplied by two corporation stops.
What is the required action?**
A. Plug or destroy the additional corporation stop(s)
B. Notify the Department of Environmental Protection (DEP)
and wait for an inspector
C. Leave the additional corporation stop in place
D. Install a Siamese connection
**Correct answer:** A
**Rationale:** Per Title 15 RCNY § 20-02(g), the Licensed
Master Plumber making the excavation must plug or destroy
the additional corporation stops. The Licensed Master Plumber
is solely responsible for locating the corporation stops, and a
separate permit is required for each stop destroyed .
---
**43. What is the required minimum depth for a water service
pipe connection?**
A. 2 feet
B. 3 feet
C. 3.5 feet
D. 6 feet
,3 | Page
**Correct answer:** C
**Rationale:** Per Title 15 RCNY § 20-03(n), all service pipe
connections must be installed at a depth of at least 3½ feet, no
more than 6 feet below ground, unless a written waiver is
obtained from the Department. Where less than 3½ feet of
cover exists, the pipe must be insulated and protected .
---
**44. What is the minimum vertical distance required between a
water service pipe connection and any other sub-surface
structure?**
A. 3 inches
B. 6 inches
C. 12 inches
D. 18 inches
**Correct answer:** B
**Rationale:** Per Title 15 RCNY § 20-03(n), a service pipe
connection must not be laid within 6 inches of any other sub-
surface structure, conduit, or pipe, nor directly below and
parallel within 6 inches of any other sub-surface structure .
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---
**45. How must backfill be placed around and one foot over a
water service pipe connection?**
A. Clean earth, free of stones, carefully tamped and compacted
B. Any available soil from the excavation
C. Sand only, no compaction required
D. Gravel and crushed stone
**Correct answer:** A
**Rationale:** Per Title 15 RCNY § 20-03(q), backfill around
and one foot over a service pipe connection must be of clean
earth, free of stones, and must be carefully tamped and
compacted in accordance with NYC DOT Standard Highway
Specifications. The remainder of the backfill must be free of
stones larger than 3 inches in diameter .
---
**46. When must a house control valve be an OS&Y (Outside
Stem and Yoke) valve?**
A. For all domestic water service connections
