Ohio's 2015 rules require every county health district to run an operation and maintenance program, and systems are enrolled under operation permits lasting up to ten years. The permit sets how often your system is inspected or serviced and how you prove it happened.
More detail
Ohio Administrative Code 3701-29-09 says no one may operate a sewage treatment system without a valid operation permit, and 3701-29-19 has each board of health build its program and phase older systems in on its own timeline. New systems also get a follow-up inspection within 12 months of approval. In practice, owners usually satisfy the permit with a service report signed by a registered service provider or with a pumping receipt, which can spare them a health department inspection fee. Terms vary by county. Delaware issues free five-year permits for gravity septic-to-leach-field systems and one-year permits for aerobic, mound, drip, and discharging systems, and charges $75 for a maintenance inspection when no report arrives. Union County enrolls every system at $10 per year on a five-year cycle. Pickaway charges $70 for either its one-year or three-year permit. Notices usually arrive by mail. When yours does, check the system type listed on it, since a mound or aerobic unit recorded as a simple gravity system (or the reverse) changes the inspection schedule.