Page 1 of 128
New Jersey Licensed Septic System Installer Exam
ACTUAL QUESTIONS AND ANSWERS LATEST
UPDATE THIS YEAR
New Jersey Licensed Septic System Installer Exam question set, written to your specifications. This
exam is based on the actual licensing requirements for a Septic System Installer as regulated by the
New Jersey Department of Environmental Protection (NJDEP) under the Sanitary Code Chapter 199 –
Standards for Individual Subsurface Sewage Disposal Systems (N.J.A.C. 7:9A, also known as the
"Chapter 199 Standards") and applicable OSHA safety regulations.
ACTUAL EXAM COVERAGE – SUMMARIZED POINT FORM
NEW JERSEY ADMINISTRATIVE CODE – N.J.A.C. 7:9A (Chapter 199)
• General Provisions: Applicability (all individual subsurface sewage disposal systems), definitions
(regulated by NJDEP), exemptions for certain repairs, permitting requirements (local Board of
Health approval)
• Site Evaluation and Soils: Percolation test (6-hour pre-soak, 1-inch drop timed, percolation rate
1-60 minutes per inch), deep hole test (mottling, water table, limiting zone), limiting zone
definition (seasonal high water table, rock, impervious layer at <48 inches for conventional
systems, <72 inches for elevated sand mounds), geotextile separator for interface, soil textural
classification (sand, sandy loam, clay loam)
• System Design – Conventional (In-ground): Septic tank (minimum 1000 gallons for 1-3
bedrooms, 1500 gallons for 4+ bedrooms), two-compartment design, baffles (inlet/outlet
effluent filter required), concrete tank thickness (3" minimum), liquid depth (48" min), gas baffle
requirement, inspection ports over inlet/outlet
• Disposal Fields (Absorption Trenches): Trenches (18-36 inches wide, 24-30 inches deep),
distribution pipes (holes on bottom, 4" diameter, gravel envelope, pea gravel, 6" washed gravel
around pipe, filter fabric required over gravel), absorption area calculation based on percolation
rate and bedrooms, bottom of trench above limiting zone (24 min separation), slope
requirements (max 20% trench, 12% field)
• Design – Alternative Systems: Elevated sand mounds (pressure dosing, 1:1 sand, offset from
limiting zone sand fill depth based on percolation rate, 60-foot setback from wells), at-grade
systems, pressure dosing systems (specs 60' separation to wells), drip irrigation systems, aerobic
treatment units (ATUs), constructed wetlands
• Mounding Analysis: Required for any system where depth of fill is needed, calculates rise of
water table due to effluent discharge, ensures mounding does not reach within 1 foot of system
bottom
• Septic Tank Installation: Trench excavation below frost depth (36" minimum depth from grade
to tank top), tank bedding (4-6 inches of clean sand or pea gravel), backfill (select materials, no
large stones), risers (required if access is below grade), water test prior to backfill, 1.5 ft
minimum cover over tank, 2 ft maximum cover without structural engineering
• Absorption Trench Construction: Heavy equipment exclusion zone (avoid compaction), trench
bottom scarification (loosen 6-9 inches), gravel envelope (12 inches below, 2 inches above
distribution pipe), distribution box (level, water test), dosing tank (if required), geotextile fabric
placement (over gravel, before cover)
, Page 2 of 128
• Material Specifications for Disposal Systems: Pipe (PVC schedule 40, ASTM D1785, holes or
slots), gravel (2-3/4 inch washed, ASTM C33), sand for elevated sand mounds (loamy sand,
specific gradation, 90% passes #4 sieve, <5% fines), geotextile fabric (USDA Type M, AASHTO
Class 2, permeability requirements)
• Permitting and Approval Process: Local Board of Health approval, NJDEP Highlands Act and
Pinelands Commission requirements, Soil Conservation District review, certified site evaluators,
design professional (engineer or sanitarian) requirements, installer licensing (NJDEP Individual
Subsurface Sewage Disposal System Installer license)
• Construction and Inspection (N.J.A.C. 7:9A, N.J.A.C. 5:23): Inspection requirements (pre-
construction site check, excavation inspection, bottom inspection, tank setting, gravel and pipe
inspection, final cover), installer to notify enforcing agency 24 hours before each required
inspection, as-built drawing submission
• Abandonment, Repair, and Replacement: Abandonment of septic tanks (crushing or filling with
flowable fill or sand), repair system design requirements (must meet current code or variance),
replacing components (tank, pipes, distribution box)
• Safety (OSHA & NJ-Specific): Excavation safety (trenching, sloping/shoring requirements at 5+ ft
depth), confined space entry (septic tank entry requires permit, ventilation, retrieval), hazardous
gases (hydrogen sulfide, methane), PPE (gloves, boots, eye protection, H2S monitor), powder-
actuated tool use
• Math and Calculations for Installers: Absorption area needed (percolation rate × gallons per day
per bedroom (150-200 gpd)), sand fill depth calculation, mounding analysis distance, grading
and slope percentages (fall/run × 100), trench length calculation
• Groundwater and Environmental Protection: Separation distances to wells (50 feet
conventional, 150 feet for shallow wells in certain areas), to surface water (100 feet), to
property lines (10 feet), to buildings (10 feet), limiting zone (seasonal high water table
determination using soil mottling and redoximorphic features)
Now, 250 MCQs (.
1. Under N.J.A.C. 7:9A, the percolation test used to determine soil absorption requires a 6-hour pre-soak
period. The percolation rate is then measured as the time required for the water level to fall by what
distance?
A) 1/2 inch
B) 1 inch
C) 2 inches
, Page 3 of 128
D) 3 inches
Correct: B – The percolation rate is measured as the time in minutes for the water level to drop 1 inch
after the pre-soak.
2. The limiting zone is defined in Chapter 199 as the seasonal high water table, bedrock, or an
impervious layer that restricts vertical movement. What is the minimum vertical separation distance
required between the bottom of a conventional absorption trench and the limiting zone?
A) 12 inches
B) 24 inches
C) 36 inches
D) 48 inches
Correct: B – N.J.A.C. 7:9A requires a minimum 2-foot (24-inch) vertical separation between the trench
bottom and the limiting zone.
3. A septic tank being installed for a 3-bedroom single-family home in New Jersey must have a minimum
liquid capacity of:
A) 750 gallons
, Page 4 of 128
B) 1000 gallons
C) 1250 gallons
D) 1500 gallons
Correct: B – For 1-3 bedrooms, the minimum septic tank liquid capacity is 1000 gallons. For 4+
bedrooms, it is 1500 gallons.
4. When installing a conventional septic tank, the invert elevation of the outlet pipe should be set at
what height relative to the inlet pipe?
A) Same elevation (no drop)
B) 1 inch lower
C) 2 to 3 inches lower
D) 6 inches lower
Correct: C – The outlet pipe invert should be 2 to 3 inches lower than the inlet invert to ensure proper
hydraulic flow and to maintain the gas baffle seal.
5. The seasonal high water table is an important site consideration. Under N.J.A.C. 7:9A, what field
observation is the primary indicator used to determine the seasonal high water table elevation?
New Jersey Licensed Septic System Installer Exam
ACTUAL QUESTIONS AND ANSWERS LATEST
UPDATE THIS YEAR
New Jersey Licensed Septic System Installer Exam question set, written to your specifications. This
exam is based on the actual licensing requirements for a Septic System Installer as regulated by the
New Jersey Department of Environmental Protection (NJDEP) under the Sanitary Code Chapter 199 –
Standards for Individual Subsurface Sewage Disposal Systems (N.J.A.C. 7:9A, also known as the
"Chapter 199 Standards") and applicable OSHA safety regulations.
ACTUAL EXAM COVERAGE – SUMMARIZED POINT FORM
NEW JERSEY ADMINISTRATIVE CODE – N.J.A.C. 7:9A (Chapter 199)
• General Provisions: Applicability (all individual subsurface sewage disposal systems), definitions
(regulated by NJDEP), exemptions for certain repairs, permitting requirements (local Board of
Health approval)
• Site Evaluation and Soils: Percolation test (6-hour pre-soak, 1-inch drop timed, percolation rate
1-60 minutes per inch), deep hole test (mottling, water table, limiting zone), limiting zone
definition (seasonal high water table, rock, impervious layer at <48 inches for conventional
systems, <72 inches for elevated sand mounds), geotextile separator for interface, soil textural
classification (sand, sandy loam, clay loam)
• System Design – Conventional (In-ground): Septic tank (minimum 1000 gallons for 1-3
bedrooms, 1500 gallons for 4+ bedrooms), two-compartment design, baffles (inlet/outlet
effluent filter required), concrete tank thickness (3" minimum), liquid depth (48" min), gas baffle
requirement, inspection ports over inlet/outlet
• Disposal Fields (Absorption Trenches): Trenches (18-36 inches wide, 24-30 inches deep),
distribution pipes (holes on bottom, 4" diameter, gravel envelope, pea gravel, 6" washed gravel
around pipe, filter fabric required over gravel), absorption area calculation based on percolation
rate and bedrooms, bottom of trench above limiting zone (24 min separation), slope
requirements (max 20% trench, 12% field)
• Design – Alternative Systems: Elevated sand mounds (pressure dosing, 1:1 sand, offset from
limiting zone sand fill depth based on percolation rate, 60-foot setback from wells), at-grade
systems, pressure dosing systems (specs 60' separation to wells), drip irrigation systems, aerobic
treatment units (ATUs), constructed wetlands
• Mounding Analysis: Required for any system where depth of fill is needed, calculates rise of
water table due to effluent discharge, ensures mounding does not reach within 1 foot of system
bottom
• Septic Tank Installation: Trench excavation below frost depth (36" minimum depth from grade
to tank top), tank bedding (4-6 inches of clean sand or pea gravel), backfill (select materials, no
large stones), risers (required if access is below grade), water test prior to backfill, 1.5 ft
minimum cover over tank, 2 ft maximum cover without structural engineering
• Absorption Trench Construction: Heavy equipment exclusion zone (avoid compaction), trench
bottom scarification (loosen 6-9 inches), gravel envelope (12 inches below, 2 inches above
distribution pipe), distribution box (level, water test), dosing tank (if required), geotextile fabric
placement (over gravel, before cover)
, Page 2 of 128
• Material Specifications for Disposal Systems: Pipe (PVC schedule 40, ASTM D1785, holes or
slots), gravel (2-3/4 inch washed, ASTM C33), sand for elevated sand mounds (loamy sand,
specific gradation, 90% passes #4 sieve, <5% fines), geotextile fabric (USDA Type M, AASHTO
Class 2, permeability requirements)
• Permitting and Approval Process: Local Board of Health approval, NJDEP Highlands Act and
Pinelands Commission requirements, Soil Conservation District review, certified site evaluators,
design professional (engineer or sanitarian) requirements, installer licensing (NJDEP Individual
Subsurface Sewage Disposal System Installer license)
• Construction and Inspection (N.J.A.C. 7:9A, N.J.A.C. 5:23): Inspection requirements (pre-
construction site check, excavation inspection, bottom inspection, tank setting, gravel and pipe
inspection, final cover), installer to notify enforcing agency 24 hours before each required
inspection, as-built drawing submission
• Abandonment, Repair, and Replacement: Abandonment of septic tanks (crushing or filling with
flowable fill or sand), repair system design requirements (must meet current code or variance),
replacing components (tank, pipes, distribution box)
• Safety (OSHA & NJ-Specific): Excavation safety (trenching, sloping/shoring requirements at 5+ ft
depth), confined space entry (septic tank entry requires permit, ventilation, retrieval), hazardous
gases (hydrogen sulfide, methane), PPE (gloves, boots, eye protection, H2S monitor), powder-
actuated tool use
• Math and Calculations for Installers: Absorption area needed (percolation rate × gallons per day
per bedroom (150-200 gpd)), sand fill depth calculation, mounding analysis distance, grading
and slope percentages (fall/run × 100), trench length calculation
• Groundwater and Environmental Protection: Separation distances to wells (50 feet
conventional, 150 feet for shallow wells in certain areas), to surface water (100 feet), to
property lines (10 feet), to buildings (10 feet), limiting zone (seasonal high water table
determination using soil mottling and redoximorphic features)
Now, 250 MCQs (.
1. Under N.J.A.C. 7:9A, the percolation test used to determine soil absorption requires a 6-hour pre-soak
period. The percolation rate is then measured as the time required for the water level to fall by what
distance?
A) 1/2 inch
B) 1 inch
C) 2 inches
, Page 3 of 128
D) 3 inches
Correct: B – The percolation rate is measured as the time in minutes for the water level to drop 1 inch
after the pre-soak.
2. The limiting zone is defined in Chapter 199 as the seasonal high water table, bedrock, or an
impervious layer that restricts vertical movement. What is the minimum vertical separation distance
required between the bottom of a conventional absorption trench and the limiting zone?
A) 12 inches
B) 24 inches
C) 36 inches
D) 48 inches
Correct: B – N.J.A.C. 7:9A requires a minimum 2-foot (24-inch) vertical separation between the trench
bottom and the limiting zone.
3. A septic tank being installed for a 3-bedroom single-family home in New Jersey must have a minimum
liquid capacity of:
A) 750 gallons
, Page 4 of 128
B) 1000 gallons
C) 1250 gallons
D) 1500 gallons
Correct: B – For 1-3 bedrooms, the minimum septic tank liquid capacity is 1000 gallons. For 4+
bedrooms, it is 1500 gallons.
4. When installing a conventional septic tank, the invert elevation of the outlet pipe should be set at
what height relative to the inlet pipe?
A) Same elevation (no drop)
B) 1 inch lower
C) 2 to 3 inches lower
D) 6 inches lower
Correct: C – The outlet pipe invert should be 2 to 3 inches lower than the inlet invert to ensure proper
hydraulic flow and to maintain the gas baffle seal.
5. The seasonal high water table is an important site consideration. Under N.J.A.C. 7:9A, what field
observation is the primary indicator used to determine the seasonal high water table elevation?
