Leach field replacement runs $5,000 to $12,000 in this market. A complete tank and field replacement runs $8,000 to $15,000, and more for engineered systems. Soil evaluation and permitting are separate line items on both.
More detail
Replacement pricing has a wide band because two houses on the same street can need different systems. The variables that move it most are soil percolation rate, available area, the water table, setback distances from wells and property lines, and whether the county will permit a conventional gravity field at all on that lot. Roughly how it breaks down in Greater Columbus and Central Ohio. A soil evaluation and system design by a registered soil scientist or engineer runs $500 to $1,500 and is required before permitting. The county permit itself is typically a few hundred dollars. A conventional gravity leach field replacement, where soil and space allow, runs $5,000 to $12,000 depending on trench footage. A full replacement including tank runs $8,000 to $15,000. Engineered alternatives cost more because the site cannot support a conventional field. Aerobic treatment units, mound systems, and drip distribution run $15,000 to $30,000 and carry ongoing maintenance and electrical costs a conventional system does not have. If a designer proposes one, the reason should be documented in the soil evaluation. What makes quotes differ legitimately: trench footage, excavation depth, whether existing components can be reused, restoration of landscaping and drives, and whether a pump chamber is needed to move effluent uphill. What should be identical across quotes: the design the soil evaluation calls for. If two contractors propose different system types for the same lot, one of them is not designing to the evaluation, and that is worth resolving before comparing prices. Septic permits, as-built drawings, and any point-of-sale requirement are held by the county health district covering the property, and they differ between districts across Franklin, Delaware, Licking, and Fairfield counties.