SOUTH CAROLINA SEPTIC TANK INSTALLER LICENSE
EXAMINATION
200 QUESTIONS WITH DETAILED RATIONALES — 2026/2027
UPDATE
1. Under SCDES Regulation 61-56, what is the minimum net liquid
capacity required for a septic tank serving a three-bedroom single-
family dwelling?
A. 750 gallons
B. 1,250 gallons
C. 1,000 gallons
D. 500 gallons
Answer: C
Rationale: Regulation 61-56 establishes a minimum net liquid capacity
of 1,000 gallons for septic tanks serving dwellings of four bedrooms or
fewer. A three-bedroom home falls within this threshold, so the tank
must meet the 1,000-gallon minimum regardless of the actual bedroom
count being lower.
2. Which installer tier is authorized to install Standard 610 Specialized
Onsite Wastewater Systems?
A. Tier 1
B. Tier 2
C. Tier 3
D. Pumper/hauler
,Answer: C
Rationale: Only Tier 3 installers are authorized to install Standard 610
specialized onsite wastewater systems. Tier 3 is the highest
classification and requires additional bonding, insurance, and
continuing education requirements beyond Tier 1 and Tier 2.
3. A homeowner asks an installer to begin constructing a septic system
before SCDES has issued the required permit. What should the installer
do?
A. Begin excavation because the homeowner accepts responsibility
B. Begin only the septic tank installation
C. Refuse to begin until the required authorization is issued
D. Begin construction if the soil appears suitable
Answer: C
Rationale: South Carolina regulations prohibit construction of an onsite
wastewater system until the Department has issued the required permit
and authorization. Proceeding without a permit exposes the installer to
fines, license revocation, and potential civil liability.
4. What minimum examination score is required for an individual
seeking South Carolina septic system installer licensure?
A. 60 percent
B. 70 percent
C. 75 percent
D. 80 percent
,Answer: D
Rationale: SCDES requires applicants seeking septic installer licensure to
pass the examination with a score of at least 80 percent. This ensures
licensed contractors demonstrate a comprehensive understanding of
regulation requirements and installation standards.
5. Which specific state regulation governs the design, installation, and
maintenance of septic tanks in South Carolina?
A. R.61-51 (Standards for Swimming Pools)
B. R.61-56 (Onsite Wastewater Systems)
C. R.61-67 (Solid Waste Management)
D. R.61-25 (Retail Food Establishments)
Answer: B
Rationale: Regulation 61-56 is the exclusive authority for onsite
wastewater treatment and disposal systems in South Carolina. It
establishes minimum site conditions, design standards, construction
criteria, and permitting requirements.
6. A Tier 1 installer is authorized to perform which of the following
installations?
A. Any type of commercial system regardless of flow
B. Pumped systems (Low Pressure Pipe)
C. New gravity-fed residential systems only
D. Repairs to existing failing systems
Answer: C
, Rationale: Tier 1 is the entry-level classification limited strictly to
installing new gravity-fed residential onsite wastewater systems. Repairs
and pressurized systems require higher tiers.
7. What is the minimum distance required between a septic tank and a
private drinking water well?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
Answer: B
Rationale: Regulation 61-56 requires a minimum setback of 50 feet
from a septic tank to a private drinking water well. This distance is a
non-negotiable health and safety regulation designed to prevent
groundwater contamination.
8. If a permit expires, what is the status of the contractor's work?
A. The contractor has a 30-day grace period to finish
B. The contractor must stop work and reapply for a new permit
C. The homeowner can authorize the continuation of work
D. The permit is automatically renewed upon payment of a late fee
Answer: B
Rationale: Permits are valid for a specific duration, often 12 months.
Once expired, a new permit application and site evaluation are required
EXAMINATION
200 QUESTIONS WITH DETAILED RATIONALES — 2026/2027
UPDATE
1. Under SCDES Regulation 61-56, what is the minimum net liquid
capacity required for a septic tank serving a three-bedroom single-
family dwelling?
A. 750 gallons
B. 1,250 gallons
C. 1,000 gallons
D. 500 gallons
Answer: C
Rationale: Regulation 61-56 establishes a minimum net liquid capacity
of 1,000 gallons for septic tanks serving dwellings of four bedrooms or
fewer. A three-bedroom home falls within this threshold, so the tank
must meet the 1,000-gallon minimum regardless of the actual bedroom
count being lower.
2. Which installer tier is authorized to install Standard 610 Specialized
Onsite Wastewater Systems?
A. Tier 1
B. Tier 2
C. Tier 3
D. Pumper/hauler
,Answer: C
Rationale: Only Tier 3 installers are authorized to install Standard 610
specialized onsite wastewater systems. Tier 3 is the highest
classification and requires additional bonding, insurance, and
continuing education requirements beyond Tier 1 and Tier 2.
3. A homeowner asks an installer to begin constructing a septic system
before SCDES has issued the required permit. What should the installer
do?
A. Begin excavation because the homeowner accepts responsibility
B. Begin only the septic tank installation
C. Refuse to begin until the required authorization is issued
D. Begin construction if the soil appears suitable
Answer: C
Rationale: South Carolina regulations prohibit construction of an onsite
wastewater system until the Department has issued the required permit
and authorization. Proceeding without a permit exposes the installer to
fines, license revocation, and potential civil liability.
4. What minimum examination score is required for an individual
seeking South Carolina septic system installer licensure?
A. 60 percent
B. 70 percent
C. 75 percent
D. 80 percent
,Answer: D
Rationale: SCDES requires applicants seeking septic installer licensure to
pass the examination with a score of at least 80 percent. This ensures
licensed contractors demonstrate a comprehensive understanding of
regulation requirements and installation standards.
5. Which specific state regulation governs the design, installation, and
maintenance of septic tanks in South Carolina?
A. R.61-51 (Standards for Swimming Pools)
B. R.61-56 (Onsite Wastewater Systems)
C. R.61-67 (Solid Waste Management)
D. R.61-25 (Retail Food Establishments)
Answer: B
Rationale: Regulation 61-56 is the exclusive authority for onsite
wastewater treatment and disposal systems in South Carolina. It
establishes minimum site conditions, design standards, construction
criteria, and permitting requirements.
6. A Tier 1 installer is authorized to perform which of the following
installations?
A. Any type of commercial system regardless of flow
B. Pumped systems (Low Pressure Pipe)
C. New gravity-fed residential systems only
D. Repairs to existing failing systems
Answer: C
, Rationale: Tier 1 is the entry-level classification limited strictly to
installing new gravity-fed residential onsite wastewater systems. Repairs
and pressurized systems require higher tiers.
7. What is the minimum distance required between a septic tank and a
private drinking water well?
A. 25 feet
B. 50 feet
C. 75 feet
D. 100 feet
Answer: B
Rationale: Regulation 61-56 requires a minimum setback of 50 feet
from a septic tank to a private drinking water well. This distance is a
non-negotiable health and safety regulation designed to prevent
groundwater contamination.
8. If a permit expires, what is the status of the contractor's work?
A. The contractor has a 30-day grace period to finish
B. The contractor must stop work and reapply for a new permit
C. The homeowner can authorize the continuation of work
D. The permit is automatically renewed upon payment of a late fee
Answer: B
Rationale: Permits are valid for a specific duration, often 12 months.
Once expired, a new permit application and site evaluation are required
