South Carolina Regulation 61-56: Onsite Wastewater Systems

Question-and-Answer flashcards summarizing key definitions, requirements, distances, capacities, licensing, and enforcement provisions of South Carolina Regulation 61-56 governing onsite wastewater systems.

What public-health reason underlies Regulation 61-56’s wastewater rules?

To prevent diseases such as dysentery, cholera, hepatitis, typhoid, and paratyphoid that spread through fecal contamination when wastewater is improperly treated or disposed.

List two of the six conditions a wastewater disposal method must meet to be considered safe under §100.

It must not contaminate any drinking-water supply and must not give rise to a public-health nuisance (other acceptable: not accessible to insects/rodents/people, not violate laws, not pollute state waters).

When is a wastewater treatment facility considered “accessible” to a property?

When county or municipal government determines it accessible and connection does not require annexation or crossing adjacent property easements (§101 Accessibility).

Define an “Alternative System” under Regulation 61-56.

A system with design modifications to the subsurface infiltration trench or geometry to meet setback or saturation offsets; only usable if the Department has an established standard.

What is an “Applicant” according to §101?

A property owner, general contractor, agent, or developer seeking a permit to construct and operate an onsite wastewater system.

What distinguishes a Conventional System from an Alternative System?

A Conventional System uses standard gravel infiltration trenches in natural soil; an Alternative System employs modified trench design or geometry approved by the Department.

Give the definition of “Effluent” in this regulation.

Liquid discharged from a septic tank, effluent pump station, or other sewage-treatment device.

What daily flow separates a small onsite wastewater system from a large one?

1,500 gallons per day (gpd).

How much repair/replacement area is required for new individual systems?

At least 50 % of the original system area; community systems require 100 % (§200.7).

Minimum vertical separation between trench bottom and zone of saturation for flows ≤ 1500 gpd?

Six (6) inches (§200.3).

Minimum depth to zone of saturation from natural surface for flows > 1500 gpd?

Thirty-six (36) inches (§200.4).

Minimum depth to rock or restrictive horizon below trench bottom?

More than twelve (12) inches (§200.5).

State the setback distance between any wastewater infiltration trench and a private well.

Seventy-five (75) feet (§200.6).

How far must trenches be from the property line?

At least five (5) feet (§200.6).

List three structures/features that must be at least 25 feet downslope from trenches.

Drainage ditch/stormwater system, basement downslope, curtain drain downslope (§200.6).

What is the smallest allowable net liquid capacity for any septic tank?

1,000 gallons (§201.1).

How is septic-tank size calculated for peak flows below 1,500 gpd (non-residential)?

Net liquid capacity = 1.5 × Peak Flow (§201.1(5)).

What additional tank volume is required per bedroom over four in a residence?

250 gallons per extra bedroom (§201.1(3)).

Name two situations where a grease trap is mandatory.

1) New food-service facilities on onsite systems; 2) Existing facilities whose systems fail due to grease (§201.2).

What is the minimum grease-trap capacity for onsite systems?

1,000 gallons (§201.2(7)).

What pipe material and minimum diameter must connect septic tanks to trenches?

Non-perforated Schedule 40 PVC, at least 3 inches in diameter (§202(1)).

Required spacing of undisturbed earth between wastewater infiltration trenches?

Seven (7) feet (§202(2)).

On sloping terrain, how should trenches be oriented?

Perpendicular to slope direction and parallel to contours (§203.1).

What fee must accompany each site-evaluation application?

$150 (§102.2).

Who may perform soil evaluations besides Department staff?

Licensed Professional Soil Classifiers or other qualified licensed professionals (§102.1(2)).

How long is a construction permit valid after issuance?

Five (5) years, provided site conditions remain unchanged (§104.2(3)).

Before construction, what site markings must an applicant complete?

Mark boundaries and corners, post front-center marker, stake proposed building corners, stub-out, tank, drain field, well, and other structures (§104.1(6)).

Describe the two criteria the Department uses to grant a variance.

1) No compromise to human health/environment; 2) Site makes strict compliance impractical and best technology is considered (§104.4).

When are new onsite systems prohibited?

When a wastewater treatment facility is accessible (§300.1).

What daily flow triggers requirement for a Land Application Permit for advanced treatment systems?

Systems > 1500 gpd or community systems using advanced methods must obtain an R.61-9 permit (§103.2).

Name the three installer license tiers and one key privilege of each.

Tier 1: Installs gravity-fed residential systems. Tier 2: Adds pumps, commercial, elevated or mounded systems, and can repair. Tier 3: Installs all systems including Specialized 610 and may self-inspect (§101, §700).

What are the annual license fees for Tier 1/Tier 2 and Tier 3 installers?

$100 for Tier 1 or Tier 2; $200 for Tier 3 (§700.1(2)(c)).

How many continuing-education hours are required every two years for a Tier 3 installer?

Eighteen (18) hours (§701.4).

What bond/insurance obligation applies only to a specific installer tier?

Tier 3 installers must maintain both bond and insurance (§703).

Under what condition may an installer self-inspect and cover a system without a Department inspector present?

If 30 minutes past the scheduled inspection time the inspector has not arrived (§702.2(1)).

What percentage of installations will the Department randomly inspect each year?

At least three percent (§702.3).

List the penalty sequence for installer violations: first, second, third offense.

First: Possible suspension ≤ 1 year; Second: suspension ≤ 3 years; Third: permanent revocation (§800.4(2)).

What is the Long-Term Acceptance Rate (LTAR)?

Flow rate (gpd/ft²) at which a mature onsite system can accept effluent without hydraulic failure (§101).

Define “Zone of Saturation” for setback calculations.

Shallowest depth where soil water pressure is zero or positive at any time during the year, identified by redox depletions or gleying (§101).

Explain Serial Distribution.

Sequential effluent flow from upper to lower trenches on slopes using drop boxes or earthen dams (§101).

What is the minimum soil cover required over alternative infiltration trench products?

At least nine (9) inches (§204.4).

State one criterion the Department evaluates when approving alternative trench products.

Structural integrity, inertness, storage volume, or maintenance of permeable interfaces (§204.3).

What construction setbacks apply to critical coastal areas?

No trench within 75 feet of delineated critical-area line or mean high-water mark (§200.6).

Describe “Expansive Soils” and their suitability for systems.

Soils with smectite clays showing very sticky/plastic properties and slickensides; deemed unsuitable (§101).

What must precede any building construction to be served by onsite wastewater?

Issuance of a permit to construct and operate the onsite system (§103.1(3)).

How is a community (cluster) system defined?

A shared collection, treatment, and disposal system serving multiple parcels or units of individually deeded property (§101).

Which regulatory reference controls minimum drinking-water separation standards?

R.61-58 State Primary Drinking Water Regulations (§103.3).

What is required before placing a mobile home on a lot needing onsite wastewater service?

A permit to construct and operate the onsite wastewater system (§103.1(3)).

What is the minimum trench aggregate depth in Standard 100/101 conventional systems?

Fourteen (14) inches total, with 7 in. below pipe, 4 in. beside, 3 in. above (§Appendix A).

Under Standard 210/211 shallow systems, how close may trench bottoms be to natural grade?

No deeper than 18 inches below natural surface (§Appendix C).

How much additional equivalency factor is added for shallow 9-inch aggregate systems?

0.09 times the conventional trench length (§Appendix C 1(e)).

What is the penalty for failing to submit self-inspection documents within two business days?

It is considered a violation of the regulation (§702.2(4)).

Define "Failing Onsite Wastewater System."

A system that discharges effluent improperly or has ceased to function (§101).

What soil texture classes are cited in LTAR sizing?

Class I, II, III, IV (used to determine LTAR based on most limiting texture) (§Appendix C 1(c)).

What is the purpose of a curtain drain?

To collect and redirect groundwater away from a wastewater infiltration area (§101).

Minimum distance from trenches to a drainage ditch or stormwater pond?

Twenty-five (25) feet (§200.6).

Which document formally authorizes construction and operation of onsite systems?

The permit issued by the South Carolina Department of Health and Environmental Control (SCDHEC) (§104.2).

On what grounds can the Department immediately suspend a permit without warning?

If there is an immediate threat to public health (§800.5).