Texas Customer Service Inspector (CSI) Exam | Questions &
Answers & Rationale | 2025/2026 | Latest Update | Instant
Download !!
1.
During a routine inspection of a residential connection, you discover the customer has installed a
hose-end fertilizer device connected to an outdoor spigot without a vacuum breaker.
What violation does this represent?
A. Excessive water use
B. High-pressure hazard
C. High health hazard cross-connection (Correct Answer)
D. Flow restriction hazard
Rationale: Fertilizer injectors can cause contaminants to backflow into the potable system without
proper backflow protection.
2.
A homeowner has installed a booster pump directly connected to a municipal supply line to increase
pressure inside the house.
What is the issue?
A. Low water quality
B. Unauthorized alteration that can cause negative pressure/back-siphonage (Correct Answer)
C. Improper meter reading
D. Improper water softener use
,Rationale: Booster pumps on a public supply line can cause dangerous vacuum conditions, drawing
contaminants into the system.
3.
A chemical feed system in a commercial building is connected to potable water through a direct
connection without an air gap.
What device is required?
A. AVB
B. Double check assembly
C. Reduced pressure principle assembly (RPZ) (Correct Answer)
D. Check valve only
Rationale: Chemical feed systems pose high hazard; RPZ protection is required.
4.
A customer complains about dirty water at one fixture only. CSI inspection finds a rusty private line
leading to an unused mop sink.
What is the likely issue?
A. Public main contamination
B. Chlorine decay
C. Stagnation in customer plumbing (Correct Answer)
D. Backflow from nearby industry
Rationale: Single-fixture problems typically originate in private plumbing, not the public system.
5.
,A restaurant kitchen has a hose attached to a wash-down sink with no backflow prevention. The hose
is long enough to enter floor drains.
What violation is present?
A. Cross meter tampering
B. High-pressure surge
C. Potential back-siphonage through a submerged hose (Correct Answer)
D. Supply line freezing
Rationale: Hoses without vacuum breakers are major cross-connection risks.
6.
At an apartment complex, irrigation lines are connected upstream of containment.
What does this require?
A. No backflow device
B. Dual check
C. RPZ assembly (Correct Answer)
D. PRV valve
Rationale: Irrigation systems are high hazard because fertilizers/pesticides may be present.
7.
A car wash uses reclaim water but still has a potable water line connected to rinse stations. A
backflow preventer is installed but is leaking.
What action must be taken?
A. Ignore until next inspection
B. Repair or replace backflow assembly immediately (Correct Answer)
C. Lower flow rate
D. Reduce chlorine feed
, Rationale: Failed assemblies cannot protect against contamination and must be repaired.
8.
A CSI finds copper piping downstream of galvanized piping in an older home.
This indicates possible:
A. Water softener corrosion
B. Dissimilar metal corrosion possibility (Correct Answer)
C. High pH formation
D. Temperature mixing hazard
Rationale: Copper after galvanized accelerates corrosion of zinc/iron.
9.
A swimming pool autofill line is directly connected to potable supply without an air gap.
What is required?
A. AVB
B. RPZ or air gap (Correct Answer)
C. Meter bypass
D. Thermal expansion tank
Rationale: Pools are high health hazard; must be isolated accordingly.
10.
A medical clinic uses potable water to feed sterilization equipment.
What level of protection is required?
Answers & Rationale | 2025/2026 | Latest Update | Instant
Download !!
1.
During a routine inspection of a residential connection, you discover the customer has installed a
hose-end fertilizer device connected to an outdoor spigot without a vacuum breaker.
What violation does this represent?
A. Excessive water use
B. High-pressure hazard
C. High health hazard cross-connection (Correct Answer)
D. Flow restriction hazard
Rationale: Fertilizer injectors can cause contaminants to backflow into the potable system without
proper backflow protection.
2.
A homeowner has installed a booster pump directly connected to a municipal supply line to increase
pressure inside the house.
What is the issue?
A. Low water quality
B. Unauthorized alteration that can cause negative pressure/back-siphonage (Correct Answer)
C. Improper meter reading
D. Improper water softener use
,Rationale: Booster pumps on a public supply line can cause dangerous vacuum conditions, drawing
contaminants into the system.
3.
A chemical feed system in a commercial building is connected to potable water through a direct
connection without an air gap.
What device is required?
A. AVB
B. Double check assembly
C. Reduced pressure principle assembly (RPZ) (Correct Answer)
D. Check valve only
Rationale: Chemical feed systems pose high hazard; RPZ protection is required.
4.
A customer complains about dirty water at one fixture only. CSI inspection finds a rusty private line
leading to an unused mop sink.
What is the likely issue?
A. Public main contamination
B. Chlorine decay
C. Stagnation in customer plumbing (Correct Answer)
D. Backflow from nearby industry
Rationale: Single-fixture problems typically originate in private plumbing, not the public system.
5.
,A restaurant kitchen has a hose attached to a wash-down sink with no backflow prevention. The hose
is long enough to enter floor drains.
What violation is present?
A. Cross meter tampering
B. High-pressure surge
C. Potential back-siphonage through a submerged hose (Correct Answer)
D. Supply line freezing
Rationale: Hoses without vacuum breakers are major cross-connection risks.
6.
At an apartment complex, irrigation lines are connected upstream of containment.
What does this require?
A. No backflow device
B. Dual check
C. RPZ assembly (Correct Answer)
D. PRV valve
Rationale: Irrigation systems are high hazard because fertilizers/pesticides may be present.
7.
A car wash uses reclaim water but still has a potable water line connected to rinse stations. A
backflow preventer is installed but is leaking.
What action must be taken?
A. Ignore until next inspection
B. Repair or replace backflow assembly immediately (Correct Answer)
C. Lower flow rate
D. Reduce chlorine feed
, Rationale: Failed assemblies cannot protect against contamination and must be repaired.
8.
A CSI finds copper piping downstream of galvanized piping in an older home.
This indicates possible:
A. Water softener corrosion
B. Dissimilar metal corrosion possibility (Correct Answer)
C. High pH formation
D. Temperature mixing hazard
Rationale: Copper after galvanized accelerates corrosion of zinc/iron.
9.
A swimming pool autofill line is directly connected to potable supply without an air gap.
What is required?
A. AVB
B. RPZ or air gap (Correct Answer)
C. Meter bypass
D. Thermal expansion tank
Rationale: Pools are high health hazard; must be isolated accordingly.
10.
A medical clinic uses potable water to feed sterilization equipment.
What level of protection is required?
