Septic soil in Shelby County, IN, by the numbers

Very limited

In Shelby County, IN, 98.6% 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 - 98.6% of it sits in USDA's most-constrained bucket. Shelby County covers 411.136 square miles and counts 45,654 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in Shelby County, IN - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Shelby County.

System cost, conventional vs. engineered

Given Shelby 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.

Shelby County's rank among Indiana counties

Nationally, Shelby County, IN is the 147-most-constrained of 3,058 rated counties for septic soil. Within Indiana alone it ranks 8 of 90.

Further reading

How this rating is built, and its real limits · Conventional vs. engineered septic systems