Glossary

Alteration Permit: Required before altering an existing sewage treatment system. Under OAC 3701-29-09(B), no one may install a new or replacement system, or alter an existing one, without a permit from the local health district.

Annual Diagnostic Sampling: A requirement for systems with off-lot discharge under the Ohio EPA NPDES permit. Samples are tested for total suspended solids, ammonia, dissolved oxygen, E. coli, and chlorine where disinfection is used. It is the homeowner's responsibility to ensure a sample is collected and reported, and not every health district provides the service.

Baffle: A barrier inside the septic tank controlling flow between compartments and keeping solids from reaching the leach field.

Effluent: The liquid leaving the septic tank after solids settle out. Its quality determines how much treatment the soil or the discharge point still has to handle.

General Permit Coverage Transfer: The Ohio EPA form required when a property with an off-lot discharging system changes ownership. Only the new homeowner's signature is needed, electronic signature is accepted, and the previous owner's details may be left blank if unknown.

GWRS: Gray Water Recycling System. Regulated alongside sewage treatment systems under OAC 3701-29.

HSTS: Household Sewage Treatment System — Ohio's regulatory term for a septic system serving one, two or three family dwellings.

Installation Permit: Required from the local health district before installing a new or replacement system. The soil and site evaluation must be complete before the application can be submitted.

Local Health District: The county or city authority that administers septic permitting, inspection and enforcement in Ohio. There are districts across all 88 counties, and they may adopt rules more stringent than the state minimum.

Notice of Intent (NOI): The two-part application for Ohio EPA NPDES coverage. Part one is completed by the local health district through Ohio EPA's eBusiness Center; part two is completed by the homeowner and carries a $200 application fee.

Notice of Termination (NOT): The Ohio EPA form submitted when an off-lot discharge ceases — for example on connection to sewer or replacement with an on-lot system. Must be signed by both the homeowner and the local health district.

NPDES Permit: National Pollutant Discharge Elimination System permit. In Ohio only Ohio EPA can issue them. General Permit OHK000004 covers household systems that discharge off lot; it took effect January 1, 2022 and expires December 31, 2026.

OAC 3701-29: The Ohio Administrative Code chapter governing sewage treatment systems, effective January 1, 2015. It sets statewide minimum standards that local health districts administer and may exceed.

Off-Lot Discharge: A system that releases treated effluent beyond the property boundary — to a ditch, stream, field tile or other surface water. These systems require an Ohio EPA NPDES permit in addition to the local operation permit.

Operation Permit: Required by the Ohio Administrative Code for all household sewage treatment systems, issued and maintained through the local health district for the life of the system. Terms and conditions are set individually, so the permit itself is the document to consult.

Operation & Maintenance Program: Under OAC 3701-29-09(I), every Ohio health district must develop and implement a local O&M program ensuring systems in its jurisdiction are monitored for maintenance and proper function.

ORC Chapter 3718: The Ohio Revised Code chapter that establishes the statutory authority for sewage treatment system regulation.

Registered Service Provider: A manufacturer trained or certified service provider registered with the local health district. Systems with off-lot discharge must operate under a service contract with one.

Riser: An extension bringing a buried tank access lid to ground level. Typically $200 to $400, and it pays for itself within about two pump-outs by removing the excavation charge.

Site Evaluation: The soil and site assessment determining what system a property can support. In Ohio it must be completed before a permit application can be submitted.

Small Flow On-Site Sewage Treatment System: A system treating up to 1,000 gallons per day, regulated alongside household systems under OAC 3701-29.

Supplemental Sewage Code: A local code adopted by a health district that goes beyond the OAC 3701-29 minimum. Summit, Stark, Mahoning and other districts publish their own, which is why requirements vary meaningfully between Ohio counties.