Riley County, KS: the USDA septic-suitability picture

Very limited

Riley County, KS's SSURGO dominant class comes back "Very limited", covering 95.5% of the county. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 95.5% of Riley County's land. The county spans 609.66 square miles, home to 72,557 people.

What this number does and doesn't tell you

USDA's survey covers the whole of Riley County, KS at once, not any single address. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.

Riley County: conventional vs. engineered cost

95.5% of Riley County carrying a "Very limited" reading changes the realistic budget here. Conventional systems run $3,000-$8,000 where they pass; where they don't, engineered alternatives (mound or aerobic treatment, whichever the health department requires) run $10,000-$40,000 - budget toward the higher figure until a perc test says otherwise.

Where this sits nationally

Among the 3,058 rated counties on this site, Riley County, KS ranks 594 most-constrained nationally, and 32 of 105 within Kansas.

Further reading

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