Compliance - Detailed Rationales - Complete Exam
New Hampshire DES Subsurface Systems | Env-Wq 1000 | Septic System Installer License | Different Title 4
TABLE OF CONTENTS
1. I. NH DES Rules Env-Wq 1000 Overview - Subsurface Systems Bureau, Installer License Requirements Exam Experience CE
2. II. Soil Evaluation - Test Pit Requirements Depth 5 Feet Minimum, Seasonal High Water Table SHWT Redoximorphic Mottling Gray Colors
Observed Water March-June Monitor Wells
3. III. Separation Distances - 24 Inches Minimum Bottom of EDA to SHWT, 48 Inches to Ledge Refusal, Perc Test Depth Proposed System
Presoak
4. IV. Percolation Test - Soil Absorption Rate Minutes Per Inch, Test at Proposed Depth, Presoak, Sizing EDA Based on Rate
5. V. Design Flow - Bedrooms Flow 4 Bedroom 600 GPD, Septic Tank Sizing 4BR 1000 Gal 5BR 1250 Gal 6BR 1500 Gal, Garbage Disposal
Increase 20 Percent or 50 Percent Larger Tank
6. VI. Setbacks Env-Wq 1008 - Septic Tank 75 Feet Private Well Leach Field 75 Feet Private Well 100 Feet Public Well, Surface Water 75
Feet Wetlands 75 Feet, Property Line 10 Feet Building 10 Feet
7. VII. Effluent Disposal Area EDA - Trenches Beds Chambers, Trench Size 12 Inches Minimum Wide 18-36 Wide Depth 12-36 Aggregate 6
Below 2 Above Pipe, D-box Level 5 Ports Max Compacted Soil Accessible
8. VIII. Mound Systems - Required When Separation Cannot Be Met In-Ground, 24 Inches Separation Maintained in Fill, 48 Inches to Ledge,
ASTM C33 Sand Fill Observation Ports Licensed Installer
9. IX. Pressure Distribution - Required Mound Large Systems Perc greater than 30 mpi, Pump Chamber Pressure Manifold Small Holes Even
Distribution
10. X. Installation Standards - Pipe Slope 1/4 Inch Per Foot Tank to D-box 2 Percent Gravity Flow, Watertight Tanks, Floodplain Requirements
No Increase Flood Level
11. XI. Soil Types - Suitable Loamy Sand Sandy Loam, Unsuitable Clay Perc greater than 60 mpi High Water Table Ledge Within 24/48 Inches
Requires Alternative
12. XII. Pumping Maintenance - Every 3-5 Years Inspection Pump When Sludge plus Scum 1/3 Tank Depth
13. XIII. Replacement Systems - Must Meet Current Env-Wq 1000 Standards New Permit Test Pits Perc Required No Grandfather
14. XIV. Holding Tanks - Last Resort No Feasible EDA DES Waiver Frequent Pumping Alarm No New Construction Generally Hardship
15. XV. Practice Questions - Original Questions Each Asked Like Real NH Septic Installer Exam - Hinted Complete Exam
16. XVI. Answer Key with Detailed Rationales - Complete Exam
,NEW HAMPSHIRE SEPTIC SYSTEM INSTALLER EXAM - PRACTICE QUESTIONS - EACH QUESTION ASKED LIKE REAL
EXAM
Based on NH DES Env-Wq 1000 Subsurface Systems Rules, Setbacks, Test Pit, Perc Test, Design Flow, Mound Systems. High Yield.
1. A homeowner in New Hampshire wants to install a septic system on a lot with high seasonal high water table at 12 inches. What is the
minimum separation distance required between bottom of leach field and seasonal high water table per NH DES rules?
A. 0 inches
B. 12 inches
C. 6 inches
D. 24 inches minimum separation - bottom of bed must be 24 inches above seasonal high water table per Env-Wq 1000 - if 12 inches water table need fill
or mound
Answer: D
Rationale: NH Env-Wq 1000 requires 24 inches separation between bottom of leach field and seasonal high water table. If water table 12 inches need
mound system or fill.
2. How to determine seasonal high water table in NH test pit?
A. Only guess
B. Only dig
C. Observe soil redoximorphic features mottling, gray colors, observed water level during wet season March-June, monitor wells
D. No method
Answer: C
Rationale: SHWT determined by redoximorphic mottling gray colors observed water wet season March-June monitor wells.
3. What is the required setback distance from a septic tank to a private well in New Hampshire?
A. 25 feet
B. 75 feet minimum from septic tank to private well, 75 feet from leach field to private well per NH Env-Wq 1008 - 100 feet to public well
C. 10 feet
D. 50 feet
Answer: B
Rationale: NH setbacks: septic tank 75 feet to private well, leach field 75 feet to private well, 100 feet to public water supply well, 50 feet to surface
water? Actually 75 feet surface water? Check Env-Wq 1008 table.
4. During a test pit evaluation in New Hampshire, you encounter ledge at 20 inches below proposed leach field. What does NH code require?
A. Can install directly on ledge
B. No requirement
C. 12 inches to ledge
D. Minimum 48 inches to ledge from bottom of system - need 48 inches to ledge, 24 inches to water table, perc test required - if ledge 20 inches below
proposed need raised system or alternative site
Answer: D
Rationale: NH requires 48 inches to ledge/refusal from bottom of leach field. Ledge at 20 inches fails, need raised/mound or new site.
5. What is required for pressure distribution in NH?
A. Required for mound systems, large systems, perc rates >30 mpi? Or when required by DES - pump chamber, pressure manifold, small holes, ensures
even distribution
B. Only gravity
C. Never required
D. No pump
Answer: A
Rationale: Pressure distribution required for mound large systems perc >30 mpi? Ensures even distribution pump chamber manifold.
6. What is required for septic system in floodplain in NH?
A. Can install anywhere
B. No requirements
C. Must meet additional DES requirements - floodplain construction, no increase flood level, watertight tanks, check local floodplain ordinance Env-Wq
D. Only tank
Answer: C
Rationale: Floodplain septic must meet DES floodplain requirements watertight tanks no increase flood level local ordinance.
7. What is required for pressure distribution in NH?
A. No pump
B. Required for mound systems, large systems, perc rates >30 mpi? Or when required by DES - pump chamber, pressure manifold, small holes, ensures
even distribution
C. Never required
D. Only gravity
Answer: B
Rationale: Pressure distribution required for mound large systems perc >30 mpi? Ensures even distribution pump chamber manifold.
8. What is required for a replacement system in NH?
A. Same as new
,B. No permit
C. Must meet current Env-Wq 1000 standards - new permit required - test pits perc tests required even if existing system - no grandfather for replacement
D. Grandfathered
Answer: C
Rationale: Replacement system must meet current standards new permit test pits perc required no grandfather.
9. What is required for a replacement system in NH?
A. No permit
B. Same as new
C. Must meet current Env-Wq 1000 standards - new permit required - test pits perc tests required even if existing system - no grandfather for replacement
D. Grandfathered
Answer: C
Rationale: Replacement system must meet current standards new permit test pits perc required no grandfather.
10. A septic installer in NH encounters a 12-inch diameter pipe from tank to D-box. What slope is required?
A. No slope
B. Flat
C. 1/4 inch per foot minimum from tank to D-box - 2% slope - 1/4 inch per foot - ensure gravity flow
D. 1 inch per foot
Answer: C
Rationale: Pipe from tank to D-box requires 1/4 inch per foot minimum slope gravity flow.
11. A client wants to install a garbage disposal. How does this affect septic design in NH?
A. Decrease flow
B. No tank change
C. Increase design flow by 20% or increase tank size - garbage disposal adds solids - NH requires 50% larger tank or increase flow - check Env-Wq 1000
D. No effect
Answer: C
Rationale: Garbage disposal increases solids, NH requires increase design flow or 50% larger tank per code.
12. What is an EDA in NH septic design?
A. Effluent Disposal Area - area where effluent disposed - includes leach field trenches beds, chamber systems - sizing based on perc rate and design
flow
B. No definition
C. Only tank
D. Only pipe
Answer: A
Rationale: EDA Effluent Disposal Area leach field trenches beds chambers sizing based on perc and flow.
13. What is the purpose of a percolation test in NH septic design?
A. To find water table
B. To find ledge
C. To determine tank size
D. To determine soil absorption rate - minutes per inch - test at depth of proposed system, presoak, measure rate, determines sizing of leach field per
Env-Wq
Answer: D
Rationale: Perc test determines soil absorption rate minutes per inch at proposed depth, presoak required, sizing leach field based on rate.
14. What is required for a mound system in New Hampshire?
A. Required when separation to water table or ledge cannot be met with in-ground - 24 inches separation maintained in mound fill, 48 inches to ledge,
observation ports, specific sand fill ASTM C33, licensed installer
B. No observation
C. No special requirements
D. Only sand
Answer: A
Rationale: Mound required when separation cannot be met in-ground, maintain 24 inches to water table in fill, 48 inches to ledge, ASTM C33 sand,
observation ports, licensed installer.
15. What is the minimum size for a leach field trench in NH?
A. 48 inches
B. Typically 12 inches wide minimum, 18-36 inches wide trenches, depth 12-36 inches, aggregate 6 inches below 2 inches above pipe
C. 6 inches wide
D. No minimum
Answer: B
Rationale: Trench typically 12 inches minimum wide 18-36 wide depth 12-36 aggregate 6 below 2 above pipe per NH.
16. How often must a septic tank be pumped in NH per DES recommendation?
A. Never
B. Every year
C. Every 3-5 years depending on use, tank size, garbage disposal - inspection every 3-5 years, pump when sludge+scum 1/3 tank depth
, D. Every 10 years
Answer: C
Rationale: DES recommends pump every 3-5 years, inspect, pump when sludge+scum 1/3 depth.
17. A 4-bedroom home in NH with 2.5 gpm well produces 600 gpd design flow. What size septic tank is required per NH rules?
A. 750 gallons
B. 1500 gallons
C. 1000 gallons minimum for up to 4 bedrooms per Env-Wq - 4 bedrooms 1000 gal tank, 5 bedrooms 1250 gal, 6 bedrooms 1500 gal - 600 gpd 4BR
needs 1000 gal
D. 500 gallons
Answer: C
Rationale: NH septic tank sizing: up to 4 bedrooms 1000 gal minimum, 5BR 1250 gal, 6BR 1500 gal per Env-Wq 1000.
18. What is the role of a D-box (distribution box) in NH septic?
A. No role
B. Only collects
C. Distributes effluent evenly to laterals - must be level, 5 ports max, set on compacted soil, accessible
D. Only stores
Answer: C
Rationale: D-box distributes effluent evenly to laterals level 5 ports max compacted soil accessible.
19. What is an EDA in NH septic design?
A. Only tank
B. Only pipe
C. No definition
D. Effluent Disposal Area - area where effluent disposed - includes leach field trenches beds, chamber systems - sizing based on perc rate and design
flow
Answer: D
Rationale: EDA Effluent Disposal Area leach field trenches beds chambers sizing based on perc and flow.
20. What is required for a replacement system in NH?
A. Grandfathered
B. Same as new
C. No permit
D. Must meet current Env-Wq 1000 standards - new permit required - test pits perc tests required even if existing system - no grandfather for replacement
Answer: D
Rationale: Replacement system must meet current standards new permit test pits perc required no grandfather.
21. A client wants to install a garbage disposal. How does this affect septic design in NH?
A. Decrease flow
B. No tank change
C. No effect
D. Increase design flow by 20% or increase tank size - garbage disposal adds solids - NH requires 50% larger tank or increase flow - check Env-Wq 1000
Answer: D
Rationale: Garbage disposal increases solids, NH requires increase design flow or 50% larger tank per code.
22. What is a holding tank and when allowed in NH?
A. Always allowed
B. No restrictions
C. Allowed only as last resort no other feasible EDA, requires DES waiver, frequent pumping, alarm, no new construction generally - existing lots hardship
D. Always for new homes
Answer: C
Rationale: Holding tank last resort no feasible EDA DES waiver frequent pumping alarm no new construction generally hardship.
23. What is an EDA in NH septic design?
A. Only tank
B. Effluent Disposal Area - area where effluent disposed - includes leach field trenches beds, chamber systems - sizing based on perc rate and design
flow
C. No definition
D. Only pipe
Answer: B
Rationale: EDA Effluent Disposal Area leach field trenches beds chambers sizing based on perc and flow.
24. How to determine seasonal high water table in NH test pit?
A. Observe soil redoximorphic features mottling, gray colors, observed water level during wet season March-June, monitor wells
B. Only guess
C. Only dig
D. No method
Answer: A
Rationale: SHWT determined by redoximorphic mottling gray colors observed water wet season March-June monitor wells.