Septic soil in Kauai County, HI, by the numbers

Very limited

In Kauai County, HI, 90.6% 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 90.6% of the county. Kauai County covers 619.84 square miles and counts 73,840 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in Kauai County, HI - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Kauai County.

System cost, conventional vs. engineered

Given Kauai County's rating, plan for the engineered-system range rather than the conventional one. 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.

Kauai County's rank among Hawaii counties

Nationally, Kauai County, HI is the 1,206-most-constrained of 3,058 rated counties for septic soil. Within Hawaii alone it ranks 3 of 3.

Before you act on this

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