Hexavalent chromium groundwater plume
Los Alamos County
Summary
A state Environment Department update reported the chromium plume is not contained within LANL property, state and LANL disagree on whether injections should continue, and the pump-and-treat system needs improvements and is at a standstill.
At a glance
- Total mentions
- 5
- Last 30 days
- 1
Discussed at 1 meeting in the last 60 days; most recently Oct 6, 2026.
Impact analysis
Remediation, lost use of well PM 3, and potential penalties all carry costs that could eventually pressure utility rates.
Residents relying on county groundwater benefit from attention to corrective actions and treatment system fixes.
Anyone depending on the regional aquifer faces ongoing uncertainty while the plume remains uncontained and treatment is stalled.
Mentions & discussions (5)
County Council - Regular Session — October 6, 2026
County staff and San Ildefonso Pueblo leaders jointly urged congressional delegation support for continued chromium plume cleanup, DOE infrastructure funding for energy communities, and new well substitution; DOE's EM office signaled support for a replacement well — a first.
County Council (Work) — July 14, 2026
The county's main PM-3 well remains offline due to the chromium plume, possibly for decades. The county believes the federal government owes a replacement well and is rethinking an Overlook/San Juan Chama drilling plan, while the Lab now plans to reclaim wastewater instead of increasing groundwater pumping.
Environmental Sustainability Board — June 18, 2026
A state Environment Department update reported the chromium plume is not contained within LANL property, state and LANL disagree on whether injections should continue, and the pump-and-treat system needs improvements and is at a standstill.
Board of Public Utilities Work Session — June 3, 2026
New sampling at well SIMR 3 on San Ildefonso land shows chromium at nearly 99 ppb — double the standard — proving the plume has moved off LANL property. Injection of treated water is halted, both state bureaus have issued compliance orders, and a final remedy is likely three to five years or more away. Well PM 3 stays offline, and residents are watching whether their drinking water supply stays protected.
Board of Public Utilities — May 20, 2026
The DOE/N3B pump-and-treat system is off at the state's direction, so the chromium plume is moving uncontrolled, though officials say drinking water wells are not threatened. About 860 pounds of chromium have been removed versus an estimated 160,000 pounds released; an adaptive site management plan is being developed and NMED will present its own update June 3.
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