All Central Ohio counties regulate residential septic systems under the same state law (ORC 3718) and the same rules (OAC 3701-29), administered by the local county health district. Permit fees, queue length, and transfer-inspection requirements differ in detail but the core engineering and approval steps are identical.
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Ohio HSTS framework: Ohio Revised Code Chapter 3718 governs residential sewage treatment systems, and Ohio Administrative Code 3701-29 sets the technical rules, administered locally by each county health district (Franklin County Public Health, Delaware Public Health District, Licking County Health Department, Fairfield Department of Health, Union County Health Department). System designs must be approved by the county health district before installation; system installers must hold Ohio installer registration; inspection cadence for ATU systems requires annual operations and maintenance contracts. Permits are typically valid for 30 days to one year after issuance depending on the district and require pre-cover inspection by a county inspector. Practical differences for Central Ohio homeowners who own property in more than one county (a common pattern for owners of rental property across the metro): the design and install scope is technically identical because the same state rules apply; the paperwork goes to different district offices; the inspector visit is the same in protocol; permit fees and queue length vary. Cost is comparable, typically $1,500 to $2,000 permit-and-inspection scope on the new install. The pumping cadence (every 3 to 5 years) is identical because the underlying engineering applies the same way everywhere. Delaware Public Health District tends to issue residential permits fastest (1 to 2 weeks); Licking County and Fairfield County run 2 to 4 weeks; Union, Madison, and Pickaway counties vary seasonally. Most Central Ohio installers operate across all of these counties with the appropriate Ohio registration.