What Putnam County, OH's soil rates for a septic system
Very limited
In Putnam County, OH, 99.3% of the surveyed land carries a "Very limited" rating for a standard septic drain field. Practically, that rules out a simple gravity system for most of the county - 99.3% of it sits in USDA's most-constrained bucket. Putnam County covers 482.544 square miles and counts 34,206 residents.
This is a county figure, not a parcel figure
Two lots a mile apart in Putnam County can carry different soil, even though they share one countywide rating. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Putnam County.
System cost, conventional vs. engineered
Given Putnam County's rating, plan for the engineered-system range rather than the conventional one. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.
Putnam County's rank among Ohio counties
Nationally, Putnam County, OH is the 49-most-constrained of 3,058 rated counties for septic soil. Within Ohio alone it ranks 11 of 87.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems