Septic suitability in Dallas County, IA
Very limited
Dallas County, IA's SSURGO dominant class comes back "Very limited", covering 65.1% of the county. That reading means a conventional system is a poor bet here - 65.1% of Dallas County lands in the strictest "very limited" bucket USDA uses. The county spans 588.23 square miles, home to 115,343 people.
What this number does and doesn't tell you
Nothing about Dallas County, IA's SSURGO figure applies to a specific address - it's a county-wide average. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Dallas County: conventional vs. engineered cost
65.1% of Dallas 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.
Dallas County's rank among Iowa counties
Among the 3,058 rated counties on this site, Dallas County, IA ranks 2,608 most-constrained nationally, and 96 of 99 within Iowa.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems