Septic soil in McPherson County, SD, by the numbers

Somewhat limited

In McPherson County, SD, 54.7% of the surveyed land carries a "Somewhat limited" rating for a standard septic drain field. That's a middle reading: not the outright failure "very limited" soil produces, but not a clean pass either. Design changes often bridge the gap. McPherson County covers 1,136.668 square miles and counts 2,307 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in McPherson County, SD - 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 McPherson County.

System cost, conventional vs. engineered

Given McPherson 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.

Where this sits nationally

Nationally, McPherson County, SD is the 2,950-most-constrained of 3,058 rated counties for septic soil. Within South Dakota alone it ranks 64 of 66.

Further reading

How this rating is built, and its real limits · How a percolation test actually works