What Washington County, TX's soil rates for a septic system
Very limited
In Washington County, TX, 92.2% of the surveyed land carries a "Very limited" rating for a standard septic drain field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 92.2% of the county. Washington County, TX is 604.196 square miles with a population of 37,810.
What Washington County's reading doesn't cover
Nothing about Washington County, TX's SSURGO figure applies to a specific address - it's a county-wide average. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Washington County will actually do.
What a system would cost here
With 92.2% of Washington 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.
How Washington County, TX compares
Nationally, Washington County, TX is the 1,013-most-constrained of 3,058 rated counties for septic soil. Within Texas alone it ranks 67 of 253.
Further reading
How this rating is built, and its real limits · Conventional vs. engineered septic systems