The Lahontan Regional Water Quality Control Board has proposed a $4.1 million settlement with the former and current owners of a South Lake Tahoe, California, property to address tetrachloroethylene (PCE) contamination affecting municipal drinking water supplies.

The proposed agreement would require Seven Springs Limited Partnership and Fox Capital Management Corporation to fund treatment, monitoring and other improvements for Lukins Brothers Water Company and Tahoe Keys Water Company. The settlement is intended to protect drinking water supplies affected by a groundwater plume originating from dry-cleaning activities at the property between 1972 and 1979.

The PCE plume extends from the junction of State Route 89 and U.S. Route 50 toward the Tahoe Keys and has contaminated wells used by the two water providers. Some affected wells have been treated while others have been closed to protect drinking water supplies.

If approved, the settlement would establish a 59-year groundwater monitoring and response program using monitoring wells to detect elevated PCE levels before they reach municipal wells. It would also fund groundwater treatment as needed, compensate the water providers for past and ongoing impacts and continue remediation at the contamination source through measures such as soil vapor extraction and targeted groundwater treatment.

The proposed agreement is subject to approval by the Lahontan Water Board, which can accept or reject its terms but cannot modify them. The board set a Nov. 20 deadline for public comments.