Septic soil in Duval County, FL, by the numbers
Very limited
79.7% of Duval County, FL's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 79.7% of the county. Duval County, FL is 762.687 square miles with a population of 1,055,159.
What Duval County's reading doesn't cover
This is a countywide, area-weighted figure across every soil survey map unit in Duval County, FL - never a reading for one specific parcel. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Duval County will actually do.
What a system would cost here
With 79.7% of Duval County rating "Very limited", a standard gravity system is not a safe assumption here. 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.
Duval County's rank among Florida counties
Nationally, Duval County, FL is the 2,054-most-constrained of 3,058 rated counties for septic soil. Within Florida alone it ranks 43 of 65.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems