NEW HAMPSHIRE SEPTIC SYSTEM INSTALLER EXAM NEWEST EVALUATED EXAM
PRACTICE 100 QUESTIONS 2026-2027|ORIGINAL QUESTIONS & ANSWERS
|DETAILED RATIONALES |HINTED COMPLETE EXAM PREP GRADED A+*INSTANT
DOWNLOAD PDF*
1. Under New Hampshire law, what must an individual generally obtain before
engaging in the business of installing subsurface sewage or waste disposal
systems?
A. A municipal building permit only
B. A permitted designer authorization
C. An installer’s permit from the Department
D. A septage hauler license
Answer: C. An installer’s permit from the Department
RSA 485-A:36 requires an installer’s permit before engaging in the business of
installing subsurface sewage or waste disposal systems, subject to specified
homeowner exemptions.
2. What is the primary administrative rule chapter governing subdivisions and
individual sewage disposal systems in New Hampshire?
A. Env-Dw 500
B. Env-Wq 1000
C. Env-Or 400
D. Env-A 1800
Answer: B. Env-Wq 1000
Env-Wq 1000 governs subdivisions and individual sewage disposal systems and
implements the applicable provisions of RSA 485-A.
3. A permitted installer is constructing a system under an approved plan. Who
is responsible for installing the system in strict accordance with the
approved plan?
,A. The property owner only
B. The local building inspector
C. The permitted designer
D. The permit holder/installer
Answer: D. The permit holder/installer
RSA 485-A:36 places responsibility on the installer permit holder for installation in
strict accordance with the approved plan.
4. How many hours of department-approved continuing education must a
permitted installer generally complete biennially?
A. 3 hours
B. 4 hours
C. 6 hours
D. 12 hours
Answer: C. 6 hours
Permitted installers must complete a minimum of 6 hours of approved continuing
education every two years.
5. A four-bedroom residence is being served by a conventional ISDS. What is
the minimum septic tank liquid capacity under the residential tank
requirement?
A. 750 gallons
B. 1,000 gallons
C. 1,250 gallons
D. 1,500 gallons
Answer: C. 1,250 gallons
For a residence or senior housing unit with up to four bedrooms, the minimum
septic tank liquid capacity is 1,250 gallons.
6. A commercial ISDS has a design flow of 500 GPD. What is the minimum
septic tank liquid capacity?
,A. 1,000 gallons
B. 1,250 gallons
C. 1,500 gallons
D. 2,000 gallons
Answer: B. 1,250 gallons
Commercial flows from 300 GPD to less than 625 GPD require a minimum liquid
tank capacity of 1,250 gallons.
7. A commercial ISDS has a design flow of 800 GPD. What is the minimum
septic tank liquid capacity?
A. 1,250 gallons
B. 1,600 gallons
C. 2,000 gallons
D. 2,400 gallons
Answer: B. 1,600 gallons
For commercial flows of at least 625 GPD but less than 4,600 GPD, the minimum
tank volume is two times the daily sewage flow: 800 × 2 = 1,600 gallons.
8. A commercial ISDS has a design flow of 5,000 GPD. What is the minimum
septic tank liquid capacity?
A. 5,000 gallons
B. 7,500 gallons
C. 10,000 gallons
D. 12,500 gallons
Answer: B. 7,500 gallons
For commercial flows of 4,600 GPD or greater, the minimum tank capacity is 1.5
times daily sewage flow: 5,000 × 1.5 = 7,500 gallons.
9. A commercial ISDS has a flow of 250 GPD. Which minimum septic tank
liquid capacity applies?
, A. 500 gallons
B. 750 gallons
C. 1,000 gallons
D. 1,250 gallons
Answer: C. 1,000 gallons
Commercial flows below 300 GPD require a minimum septic tank liquid capacity of
1,000 gallons.
10.A combined residential and commercial ISDS consists of a residential
component and a commercial component. How is the minimum tank
capacity determined?
A. Use only the residential requirement
B. Use only the commercial requirement
C. Add the applicable residential and commercial minimum capacities
D. Use the larger of the two capacities
Answer: C. Add the applicable residential and commercial minimum capacities
For combined residential and commercial uses, the required minimum capacity is
the residential minimum plus the commercial minimum.
11.A four-bedroom residence has a percolation rate of 8 minutes per inch.
What is the required conventional stone-and-pipe bed size?
A. 750 square feet
B. 900 square feet
C. 1,000 square feet
D. 1,200 square feet
Answer: C. 1,000 square feet
Table 1016-1 gives 1,000 square feet for a four-bedroom residential use at an 8-
minute-per-inch percolation rate.
12.A three-bedroom residence has a percolation rate of 12 minutes per inch.
What is the conventional stone-and-pipe bed size?
PRACTICE 100 QUESTIONS 2026-2027|ORIGINAL QUESTIONS & ANSWERS
|DETAILED RATIONALES |HINTED COMPLETE EXAM PREP GRADED A+*INSTANT
DOWNLOAD PDF*
1. Under New Hampshire law, what must an individual generally obtain before
engaging in the business of installing subsurface sewage or waste disposal
systems?
A. A municipal building permit only
B. A permitted designer authorization
C. An installer’s permit from the Department
D. A septage hauler license
Answer: C. An installer’s permit from the Department
RSA 485-A:36 requires an installer’s permit before engaging in the business of
installing subsurface sewage or waste disposal systems, subject to specified
homeowner exemptions.
2. What is the primary administrative rule chapter governing subdivisions and
individual sewage disposal systems in New Hampshire?
A. Env-Dw 500
B. Env-Wq 1000
C. Env-Or 400
D. Env-A 1800
Answer: B. Env-Wq 1000
Env-Wq 1000 governs subdivisions and individual sewage disposal systems and
implements the applicable provisions of RSA 485-A.
3. A permitted installer is constructing a system under an approved plan. Who
is responsible for installing the system in strict accordance with the
approved plan?
,A. The property owner only
B. The local building inspector
C. The permitted designer
D. The permit holder/installer
Answer: D. The permit holder/installer
RSA 485-A:36 places responsibility on the installer permit holder for installation in
strict accordance with the approved plan.
4. How many hours of department-approved continuing education must a
permitted installer generally complete biennially?
A. 3 hours
B. 4 hours
C. 6 hours
D. 12 hours
Answer: C. 6 hours
Permitted installers must complete a minimum of 6 hours of approved continuing
education every two years.
5. A four-bedroom residence is being served by a conventional ISDS. What is
the minimum septic tank liquid capacity under the residential tank
requirement?
A. 750 gallons
B. 1,000 gallons
C. 1,250 gallons
D. 1,500 gallons
Answer: C. 1,250 gallons
For a residence or senior housing unit with up to four bedrooms, the minimum
septic tank liquid capacity is 1,250 gallons.
6. A commercial ISDS has a design flow of 500 GPD. What is the minimum
septic tank liquid capacity?
,A. 1,000 gallons
B. 1,250 gallons
C. 1,500 gallons
D. 2,000 gallons
Answer: B. 1,250 gallons
Commercial flows from 300 GPD to less than 625 GPD require a minimum liquid
tank capacity of 1,250 gallons.
7. A commercial ISDS has a design flow of 800 GPD. What is the minimum
septic tank liquid capacity?
A. 1,250 gallons
B. 1,600 gallons
C. 2,000 gallons
D. 2,400 gallons
Answer: B. 1,600 gallons
For commercial flows of at least 625 GPD but less than 4,600 GPD, the minimum
tank volume is two times the daily sewage flow: 800 × 2 = 1,600 gallons.
8. A commercial ISDS has a design flow of 5,000 GPD. What is the minimum
septic tank liquid capacity?
A. 5,000 gallons
B. 7,500 gallons
C. 10,000 gallons
D. 12,500 gallons
Answer: B. 7,500 gallons
For commercial flows of 4,600 GPD or greater, the minimum tank capacity is 1.5
times daily sewage flow: 5,000 × 1.5 = 7,500 gallons.
9. A commercial ISDS has a flow of 250 GPD. Which minimum septic tank
liquid capacity applies?
, A. 500 gallons
B. 750 gallons
C. 1,000 gallons
D. 1,250 gallons
Answer: C. 1,000 gallons
Commercial flows below 300 GPD require a minimum septic tank liquid capacity of
1,000 gallons.
10.A combined residential and commercial ISDS consists of a residential
component and a commercial component. How is the minimum tank
capacity determined?
A. Use only the residential requirement
B. Use only the commercial requirement
C. Add the applicable residential and commercial minimum capacities
D. Use the larger of the two capacities
Answer: C. Add the applicable residential and commercial minimum capacities
For combined residential and commercial uses, the required minimum capacity is
the residential minimum plus the commercial minimum.
11.A four-bedroom residence has a percolation rate of 8 minutes per inch.
What is the required conventional stone-and-pipe bed size?
A. 750 square feet
B. 900 square feet
C. 1,000 square feet
D. 1,200 square feet
Answer: C. 1,000 square feet
Table 1016-1 gives 1,000 square feet for a four-bedroom residential use at an 8-
minute-per-inch percolation rate.
12.A three-bedroom residence has a percolation rate of 12 minutes per inch.
What is the conventional stone-and-pipe bed size?
