South Carolina Septic Tank Contractor Licensing Exam 2025 – actual Exam Format Questions & Answers with Rationales | 100% Verified | Graded A+

South Carolina Septic Tank Contractor
Licensing Exam 2025 – actual Exam
Format Questions & Answers with
Rationales | 100% Verified | Graded A+

Question 1 To become licensed as a septic system installer in South Carolina, what minimum
score must you achieve on the examination? A. 70% B. 75% C. 80% D. 90%

C. 80% Rationale: Per Regulation 61-56.1, applicants must pass the exam with 80% or better.
The exam tests knowledge of Regulation 61-56 topics like design, installation, and permitting.



Question 2 What is the primary regulatory document governing onsite wastewater systems in
South Carolina? A. South Carolina Building Code B. Regulation 61-56: Onsite Wastewater
Systems C. South Carolina Plumbing Standards D. Environmental Health Code only

B. Regulation 61-56: Onsite Wastewater Systems Rationale: Regulation 61-56 outlines
standards for septic system design, permitting, installation, and maintenance to protect public
health and water quality.



Question 3 Before installing a septic system for a new residential home, what must be obtained
from SCDES? A. Only a building permit B. Site approval and Permit to Construct C. Soil test
only D. Hauler license

B. Site approval and Permit to Construct Rationale: South Carolina law requires SCDES site
evaluation and a Permit to Construct for all onsite systems to ensure suitability and prevent
environmental contamination.



Question 4 What is the minimum septic tank size for a 3-bedroom residence under Regulation
61-56? A. 750 gallons B. 1,000 gallons C. 1,200 gallons D. 1,500 gallons

B. 1,000 gallons Rationale: Table 2 in Regulation 61-56 requires 1,000 gallons for up to 3
bedrooms (based on 150 gallons/bedroom flow estimate), ensuring adequate retention time.

, Question 5 Which of the following is NOT a requirement for septic tank construction materials?
A. Watertight and corrosion-resistant B. Minimum 4-inch wall thickness for poured-in-place
concrete C. Reinforced with steel bars D. Approved by a national testing laboratory

C. Reinforced with steel bars Rationale: Regulation 61-56 requires watertight, durable
materials (concrete, fiberglass, etc.) tested by NSF/ANSI Standard 40, but reinforcement is
specified as wire mesh or equivalent, not mandatory steel bars for all types.



Question 6 What is the required setback distance from a septic tank to a property line? A. 5 feet
B. 10 feet C. 15 feet D. 20 feet

A. 5 feet Rationale: Section 300 of Regulation 61-56 mandates a 5-foot setback from tanks to
property lines to allow access while minimizing neighbor impacts.



Question 7 For a gravity-fed residential system, who can perform the final inspection if the
SCDES inspector is late? A. Any homeowner B. A licensed Tier 2 installer using Form D-3978
C. The general contractor D. No one; installation must stop

B. A licensed Tier 2 installer using Form D-3978 Rationale: If the inspector arrives >30
minutes late, licensed installers may self-inspect and submit Form D-3978 (Contractor Approval
to Operate) per SCDES policy.



Question 8 What must be included in a septic permit application? A. Site plan, soil evaluation,
and system design B. Only the tank size C. Proof of insurance only D. Hauling manifest

A. Site plan, soil evaluation, and system design Rationale: Applications require
comprehensive documentation (site plan, soil profile, design) to verify compliance with
Regulation 61-56 standards.



Question 9 True or False: Additives or treatments are recommended for septic tanks to improve
performance. A. True B. False

B. False Rationale: SCDES FAQs state additives may harm systems and hasten failure; natural
bacterial action suffices, and some states ban them.