Coconino County outlines on‑site wastewater requirements, alternatives for Valley properties

Zachary Burth, an environmental quality specialist for Coconino County, told a Valley audience that shallow soils and bedrock make conventional septic systems impractical for much of the area and explained the county's permitting and site investigation process and the on‑site wastewater alternatives the county commonly permits.

Burth said Coconino County issues a construction authorization and, after installation and final inspection, a discharge authorization that allows a residence to be connected. "Once I get that the DA is issued. So again you're good to flush is what the operate means," he said.

Why it matters: Valley parcels often lack the 48 inches of native soil required beneath a conventional disposal field under current Arizona rules, Burth said. That shortfall drives the frequent use of pretreated, alternate systems such as aerobic treatment units with chlorination or UV disinfection, mound systems, composting toilets and, in limited cases, vault‑and‑haul tanks.

Burth described the site investigation the county requires before design: a minimum of three test holes (two in a proposed primary disposal area and one reserve), dug to refusal (bedrock), with soil horizons logged and a soil absorption rate assigned from standard texture tests. "Three test…