Arizona Stormwater Inspector
Certification Exam Practice Questions
And Correct Answers (Verified Answers)
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1. A construction site subject to the federal stormwater program must
obtain coverage under an NPDES permit when:
A. soil is disturbed on more than 1 acre, drainage is toward a storm
sewer, and best management practices are used
B. soil is disturbed on more than 1 acre C. soil is disturbed on any
amount of land within 500 feet of a storm drain
D. soil is disturbed on 10 or more acres
Correct Answer: B. Soil is disturbed on more than 1 acre because federal
regulations require NPDES stormwater permit coverage for construction
activities disturbing one acre or more of land to control erosion and
sediment discharge.
2. Which of the following pollutants is of greatest concern for sediment-
laden stormwater from a construction site?
A. Chlorides
B. Heavy metals
C. Nutrients
D. Sediment
,Correct Answer: D. Sediment because soil particles are the principal
pollutant from construction stormwater and can smother aquatic habitat
and transport other contaminants.
3. An effective silt fence should be installed:
A. Along the toe of a slope to intercept sheet flow B. Along the
contour at the downslope perimeter of disturbed areas
C. At the top of a slope above the disturbed area
D. Across a stream channel as the primary sediment control
Correct Answer: B. Along the contour at the downslope perimeter of
disturbed areas because this placement maximizes sediment capture from
overland flow.
4. Which BMP is most appropriate for preventing sediment from leaving
a construction site?
A. Chemical flocculants
B. Street sweeping
C. Stabilized construction entrance
D. Riprap outlet protection
Correct Answer: C. Stabilized construction entrance because it reduces
tracking of soil onto public roads and thereby prevents sediment off-site.
5. Under Arizona’s stormwater rules, a Stormwater Pollution Prevention
Plan (SWPPP) must:
A. Be optional unless requested by a regulator
B. Only include water quality sampling data
C. Identify potential pollutant sources and control measures
D. Only be kept on file after the project ends
Correct Answer: C. Identify potential pollutant sources and control
measures because a SWPPP must document pollutants and BMPs to
minimize stormwater impacts.
6. Temporary seeding on a disturbed area must be applied:
A. Only at final site stabilization
, B. When construction ceases for more than 5 days C. Within 14 days
of inactivity
D. Only during the rainy season
Correct Answer: C. Within 14 days of inactivity because timely
establishment of vegetation minimizes erosion and sediment runoff.
7. The purpose of a stormwater detention basin is to:
A. Discharge stormwater immediately to prevent flooding
B. Slow runoff and allow sediment to settle before discharge
C. Increase the peak flow rate from a site
D. Eliminate groundwater recharge
Correct Answer: B. Slow runoff and allow sediment to settle before
discharge because detention basins temporarily hold water and release
cleaner, slower flows.
8. Which inspection frequency meets federal stormwater permit
requirements for active construction sites?
A. Monthly
B. Weekly and within 24 hours of a storm event
C. Annually
D. Only after complaints
Correct Answer: B. Weekly and within 24 hours of a storm event because
frequent inspections ensure BMP effectiveness and compliance.
9. A key indicator that a sediment basin needs maintenance is:
A. Vegetation growth
B. Dry weather conditions
C. Sediment accumulation reducing capacity
D. Clear water discharge
Correct Answer: C. Sediment accumulation reducing capacity because
decreased storage reduces the basin’s function to settle out sediment.
Certification Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
Download Pdf
1. A construction site subject to the federal stormwater program must
obtain coverage under an NPDES permit when:
A. soil is disturbed on more than 1 acre, drainage is toward a storm
sewer, and best management practices are used
B. soil is disturbed on more than 1 acre C. soil is disturbed on any
amount of land within 500 feet of a storm drain
D. soil is disturbed on 10 or more acres
Correct Answer: B. Soil is disturbed on more than 1 acre because federal
regulations require NPDES stormwater permit coverage for construction
activities disturbing one acre or more of land to control erosion and
sediment discharge.
2. Which of the following pollutants is of greatest concern for sediment-
laden stormwater from a construction site?
A. Chlorides
B. Heavy metals
C. Nutrients
D. Sediment
,Correct Answer: D. Sediment because soil particles are the principal
pollutant from construction stormwater and can smother aquatic habitat
and transport other contaminants.
3. An effective silt fence should be installed:
A. Along the toe of a slope to intercept sheet flow B. Along the
contour at the downslope perimeter of disturbed areas
C. At the top of a slope above the disturbed area
D. Across a stream channel as the primary sediment control
Correct Answer: B. Along the contour at the downslope perimeter of
disturbed areas because this placement maximizes sediment capture from
overland flow.
4. Which BMP is most appropriate for preventing sediment from leaving
a construction site?
A. Chemical flocculants
B. Street sweeping
C. Stabilized construction entrance
D. Riprap outlet protection
Correct Answer: C. Stabilized construction entrance because it reduces
tracking of soil onto public roads and thereby prevents sediment off-site.
5. Under Arizona’s stormwater rules, a Stormwater Pollution Prevention
Plan (SWPPP) must:
A. Be optional unless requested by a regulator
B. Only include water quality sampling data
C. Identify potential pollutant sources and control measures
D. Only be kept on file after the project ends
Correct Answer: C. Identify potential pollutant sources and control
measures because a SWPPP must document pollutants and BMPs to
minimize stormwater impacts.
6. Temporary seeding on a disturbed area must be applied:
A. Only at final site stabilization
, B. When construction ceases for more than 5 days C. Within 14 days
of inactivity
D. Only during the rainy season
Correct Answer: C. Within 14 days of inactivity because timely
establishment of vegetation minimizes erosion and sediment runoff.
7. The purpose of a stormwater detention basin is to:
A. Discharge stormwater immediately to prevent flooding
B. Slow runoff and allow sediment to settle before discharge
C. Increase the peak flow rate from a site
D. Eliminate groundwater recharge
Correct Answer: B. Slow runoff and allow sediment to settle before
discharge because detention basins temporarily hold water and release
cleaner, slower flows.
8. Which inspection frequency meets federal stormwater permit
requirements for active construction sites?
A. Monthly
B. Weekly and within 24 hours of a storm event
C. Annually
D. Only after complaints
Correct Answer: B. Weekly and within 24 hours of a storm event because
frequent inspections ensure BMP effectiveness and compliance.
9. A key indicator that a sediment basin needs maintenance is:
A. Vegetation growth
B. Dry weather conditions
C. Sediment accumulation reducing capacity
D. Clear water discharge
Correct Answer: C. Sediment accumulation reducing capacity because
decreased storage reduces the basin’s function to settle out sediment.
