ADEQ warns rising nitrates in East Verde Estates wells; proposes nitrogen management area and community outreach

The Arizona Department of Environmental Quality told the Gila County Board of Supervisors that groundwater nitrate levels in the East Verde Estates area have risen over years, in some cases exceeding the federal drinking water standard, and proposed beginning the public process to consider designating the neighborhood a nitrogen management area (NMA).

Trevor Bajori, director of ADEQ’s Water Quality Division, introduced the briefing and turned the presentation to Deputy Director Randy Mattis, who described the technical case: East Verde Estates has more than 200 septic systems clustered near public‑water system wells; sampling detected sucralose (an indicator of human wastewater) alongside rising nitrate levels, and trends show increases beginning to exceed the federal drinking‑water standard around 2023.

Mattis said a nitrogen management area is a regulatory designation under the Arizona Administrative Code intended to reduce nitrogen loading to groundwater over time. An NMA does not require immediate removal of existing septic systems; rather, when a system fails or is replaced, the replacement must use technology that better removes nitrates or the household can connect to a public water system if one is available. ADEQ emphasized maintenance of existing systems (pumping, repairs) remains allowable.

ADEQ outlined next steps: community meetings to explain the issue, gather input and discuss options (including potential centralized treatment or effluent collection systems), review comments and, if necessary, hold a formal public hearing. The ADEQ director will consider technical data and public input before deciding whether designation is “reasonable and prudent” for this site. Mattis said grants or subsidy options could be explored to reduce homeowner costs.

Supervisors asked about cost comparisons between individual household treatment and a centralized treatment option; ADEQ said it would examine centralized effluent collection systems and look for funding options. Supervisors also raised skepticism about whether a replacement‑only rule would substantially reduce loading because many septic systems remain; ADEQ said the designation aims to slow and reduce long‑term loading and protect vulnerable users, including infants, who are at higher risk from elevated nitrate levels.

ADEQ told the board it will proceed with community engagement and provide follow‑up materials; no formal county action was required at the meeting.