Septic suitability in DuPage County, IL

Very limited

DuPage County, IL: USDA's soil survey calls 97.2% of the county "Very limited" for a septic leach field. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 97.2% of DuPage County's land. The county spans 327.892 square miles, home to 937,142 people.

What this number does and doesn't tell you

USDA's survey covers the whole of DuPage County, IL 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.

DuPage County: conventional vs. engineered cost

97.2% of DuPage 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, DuPage County, IL ranks 346 most-constrained nationally, and 17 of 101 within Illinois.

Further reading

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