GLOSSARY · 33 TERMS

Aerobic septic terms, defined with their rules

The words Texas and North Carolina rules use for aerobic systems and the people who maintain them. Each definition carries its citation and links to the page that explains the rule in full.

Both states

Aerobic treatment unit (ATU): A treatment unit that pumps air into the wastewater so aerobic bacteria break it down before it is dispersed. Texas rules treat it as secondary treatment, which must be maintained under contract. North Carolina permits it as advanced pretreatment, usually Type Va or Vc.; 30 TAC §285.91(12), Table XII · 15A NCAC 18E .1301(b), Table XXXII More on Aerobic treatment unit

Texas · 30 TAC Chapter 285

Authorization to Construct: The permit to build an OSSF. TCEQ’s annual “Types of Systems Installed” reports count them by county and by system type, which is what the Texas permit figures on this site are.; TCEQ “Types of Systems Installed” reports, 2015–2025 More on Authorization to Construct
Authorized agent: A local government that TCEQ has authorized to run the OSSF program in its area: usually a county, sometimes a city, health district or river authority. Where there is none, the TCEQ regional office permits systems directly.; 30 TAC §285.3(a)(2) More on Authorized agent
BOD5 and TSS (five-day biochemical oxygen demand and total suspended solids): Effluent quality tests. Systems other than single-family homes need one grab sample a year, with each result not exceeding 65 mg/l.; 30 TAC §285.91(4), Table IV More on BOD5 and TSS
Drip irrigation (drip emitter): Dispersal of treated effluent through emitters in tubing below the surface. Table XII lists it among the disposal methods paired with secondary treatment that require maintenance under contract.; 30 TAC §285.91(12), Table XII More on Drip irrigation
Electronic monitoring: Monitoring with automatic telephone or radio access that tells the provider when a component fails and tracks the disinfection supply. A system that has it may be tested twice a year instead of every four months.; 30 TAC §285.7(e)(3) More on Electronic monitoring
Emergency repair: A repair made to abate an immediate, serious and dangerous health hazard that does not alter the system’s planning materials or function, such as a tank lid, a riser or a disinfection device. The work may start at once; written notice goes to the permitting authority within 72 hours after starting.; 30 TAC §285.35 More on Emergency repair
Fecal coliform: The alternative disinfection test: the result must not exceed 200 MPN per 100 ml. A system may use it in place of the chlorine residual test.; 30 TAC §285.91(4), Table IV More on Fecal coliform
Figure 3 (Sample Testing and Reporting Record): The state’s model maintenance report: the test date, the property and permit, the person inspecting, the inspection items and the test results. Some permitting authorities use their own form instead.; 30 TAC §285.90(3) More on Figure 3
Initial two-year service policy: The first two years of maintenance on a new system, effective from the date it is first used. After it ends, a single-family owner renews the contract or may maintain the system personally.; 30 TAC §285.7(c) · §285.7(d)(4) More on Initial two-year service policy
Maintenance contract: The written agreement between the owner and a maintenance provider. It must list what is covered, the complaint response time, the responsible provider, how often the system is maintained, tested and reported, who maintains the disinfection unit, and the provider’s address and phone.; 30 TAC §285.7(d)(1) More on Maintenance contract
Maintenance provider (MP): The TCEQ-licensed individual responsible for each maintenance contract, each report and each technician’s work. Only the provider may sign maintenance reports.; 30 TAC §285.64(a) · §285.7(b)(3) More on Maintenance provider
Maintenance technician (MT): A TCEQ registrant who may perform maintenance only under a provider’s direct supervision on site or in direct communication with the provider. A technician may not sign reports or advertise as a provider.; 30 TAC §285.64(b) More on Maintenance technician
On-site sewage facility (OSSF): The Texas term for a septic system of any kind, from a conventional tank and drainfield to an aerobic system with spray or drip. 30 TAC Chapter 285 governs how they are permitted, maintained and reported.; 30 TAC Chapter 285 More on On-site sewage facility
Permitting authority: The body that permits OSSFs and receives maintenance reports: TCEQ’s executive director, or the authorized agent where a local government has an approved OSSF order, ordinance or resolution.; 30 TAC §285.2(51) · §285.3(a)(2) More on Permitting authority
Registered transporter: The only kind of hauler an owner may use to take away treatment tank contents: a person registered with the TCEQ executive director. Owners must have tanks pumped on a regular basis; the rule sets no interval.; 30 TAC §285.39(b) More on Registered transporter
Reporting deadline (14 days): Each maintenance report goes to the permitting authority and the owner within 14 days after the test is performed.; 30 TAC §285.7(e)(1)(B) More on Reporting deadline
Surface application (spray): Dispersal of treated effluent by spraying it on the ground surface. The effluent must be disinfected first, and the pump tank must meet the Table IV result at each test.; 30 TAC §285.91(4), Table IV More on Surface application
Table IV: The table that sets how often an aerobic system is tested and what result it must meet. A system with surface application is tested at least every four months.; 30 TAC §285.91(4) More on Table IV
Total chlorine residual: The disinfection test on a spray system: at least 0.1 mg/l of total chlorine residual in the pump tank. A reading of “trace” is below that, so it fails.; 30 TAC §285.91(4), Table IV More on Total chlorine residual

North Carolina · 15A NCAC 18E

30-day inspection report: The Management Entity sends each inspection report to the owner, the LHD and the manufacturer within 30 days of the inspection.; 15A NCAC 18E .1304(c) More on 30-day inspection report
48-hour repair notice: When an inspection shows a system needs repairs, the Management Entity notifies the LHD within 48 hours.; 15A NCAC 18E .1304(d) More on 48-hour repair notice
Advanced pretreatment (Type Va, Vc): Treatment beyond a septic tank before dispersal, Type V or VI in Table XXXII. For Type Va and Vc at or under 1,500 gpd, the Management Entity inspects twice a year after a quarterly first year, and the LHD inspects once a year.; 15A NCAC 18E .1301(b), Table XXXII More on Advanced pretreatment
Certified subsurface operator: The minimum certification for anyone operating a system that Table XXXII assigns to a Management Entity. The Water Pollution Control System Operators Certification Commission (WPCSOCC) issues it.; 15A NCAC 18E .1304(a) · 15A NCAC 08G More on Certified subsurface operator
Local health department (LHD): The county or district health department that permits systems, inspects them on the Table XXXII schedule, and receives the operator’s inspection reports and repair notices.; 15A NCAC 18E .1301(b) · .1304(c) More on Local health department
Low pressure pipe (LPP, Type IVa): A pressure-dosed distribution system, Type IVa in Table XXXII. The Management Entity inspects it at least twice a year from the start, and the LHD every three years.; 15A NCAC 18E .1301(b), Table XXXII More on Low pressure pipe
Management Entity: The person or company the owner designates with primary responsibility for operating the system: a private certified operator, or a public Management Entity with a certified operator.; 15A NCAC 18E .0105(58) More on Management Entity
Non-renewal notice: When the owner or the Management Entity chooses not to renew the contract, the Management Entity notifies the LHD and, where applicable, the manufacturer. The rule sets no number of days; the contract does.; 15A NCAC 18E .1304(f) · .1303(b)(4) More on Non-renewal notice
One-third rule (septic tank pumping trigger): The entire contents of all septic tank compartments are removed once the scum and sludge together are more than one-third of the liquid depth in any compartment. North Carolina sets no calendar interval for pumping.; 15A NCAC 18E .1303(a)(3) More on One-third rule
Operation Permit (OP): The permit to operate a system. For advanced pretreatment, the owner must prove a Management Entity contract is in place before it is issued or re-issued, and for Type V and VI systems it expires after five years.; 15A NCAC 18E .1302(c) · .0205(g) More on Operation Permit
Residential wastewater treatment system (RWTS): A residential treatment unit approved under Section .1500 and meeting NSF/ANSI 40, classified Type Vc for flows up to 1,500 gallons per day.; 15A NCAC 18E .1301(b), Table XXXII More on Residential wastewater treatment system
Table XXXII: The table that classifies every system type and sets two inspection frequencies for each: the Management Entity’s minimum and the local health department’s compliance inspection.; 15A NCAC 18E .1301(b) More on Table XXXII
Visual Inspection Protocol (VIP): The manufacturer’s inspection routine for advanced pretreatment: a visual check of the critical components and of the effluent for solids, clarity, color and odor, with field tests of pH, turbidity and dissolved oxygen.; 15A NCAC 18E .1302(d)(3)(A) More on Visual Inspection Protocol

Definitions restate the rule pages on this site as of Oct 13, 2026. How we research and check them. Not legal advice. Verify with your permitting authority or local health department.