Septic suitability in Montgomery County, TX
Very limited
Montgomery County, TX's SSURGO dominant class comes back "Very limited", covering 91.4% of the county. That reading means a conventional system is a poor bet here - 91.4% of Montgomery County lands in the strictest "very limited" bucket USDA uses. For scale: 1,042.178 square miles and 749,613 people call Montgomery County home.
Before you rely on this for one lot
Montgomery County's rating is an average across the whole county, not a promise about any one lot inside it. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).
Budgeting for a system in Montgomery County, TX
Montgomery County's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. 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, Montgomery County, TX ranks 1,111 most-constrained nationally, and 81 of 253 within Texas.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems