Today, the U.S. Environmental Protection Agency (EPA) announced that Sixteen to One Mine, one of California’s oldest operational gold mines, has agreed to an Administrative Order on Consent requiring the mine to install a new treatment system that will remove pollutants from mine drainage before entering local waters. The mine was found to be in violation of its permit under the U.S. Clean Water Act after consistently discharging mine-influenced water that exceeded limits on pollutants. The Sixteen to One Mine, located in the Tahoe National Forest, discharges into Kanaka Creek, a tributary of the Yuba, Feather, and Sacramento Rivers.

“Under the Clean Water Act, industrial wastewater must be treated before it can be discharged,” said EPA Pacific Southwest Regional Director of the Enforcement and Compliance Assurance Division Amy Miller. “These upgrades will be critical to protecting public health and water quality in Sierra County.”

The agreement announced today addresses elevated pollutant levels by requiring the mine to install a system to treat total suspended solids, antimony, arsenic, cadmium, copper, lead, nickel, and pH to levels at or below permit limits. The Sixteen to One Mine has agreed to submit sampling and treatment plans, install an approved water treatment technology, repair stormwater management features in disrepair, update its stormwater management plan, and apply for coverage under the California Statewide Industrial General Permit.

The Sixteen to One Mine has 220 days to complete this work. The facility will report sampling results to EPA for three years to demonstrate the treatment system’s effectiveness, ensure compliance with the permit, and protect the water quality of Kanaka Creek.

This settlement seeks to improve surface water quality by ensuring dischargers comply with permit requirements. For more information on an EPA initiative to increase such compliance, please visit:

For more information on NPDES Permits in US EPA’s Pacific Southwest Region, please visit: