South Lake Tahoe Groundwater Contamination Investigation Continues

More than 150 Property Owners to Receive Questionnaires

SOUTH LAKE TAHOE, Calif. – Amid continuing concern about the extent of Perchloroethylene (PCE) groundwater contamination in South Lake Tahoe, the Lahontan Regional Water Quality Control Board (Lahontan Water Board) is expanding its investigation into potential sources.

Multiple drinking water supply wells in the South Y area (near intersection of State Route 89 and Interstate 50), including those operated by three different water suppliers, previously were found to be affected or threatened by PCE commonly used in dry cleaning businesses, printing, and auto body shops and used in products from other industries. Most recently, after a review of available records, more than 150 properties within the City of South Lake Tahoe were identified as sites where past or current businesses likely used, stored and/or disposed of PCE or PCE-containing products.

The Lahontan Water Board issued 233 investigative orders to identify potential source properties that may have contributed to the regional PCE groundwater contamination.  Current and former property owners and operators of the more than 150 sites are being required to complete and return a combined 233 questionnaires that are being mailed to them and inquire about their use, storage and/or disposal of PCE and PCE-containing products on their properties. If a property is found to have a higher probability of contamination – for example, where PCE has been found in the soil – the owner or operator will be required to provide more extensive information and cooperate with Lahontan Water Board staff for onsite testing. Failure to comply with the investigative orders is subject to fines up to $1,000 per day of violation.

“This critical step will help identify potential pollution sources of the regional PCE plume.  With this knowledge we can protect our drinking water supplies and expedite the cleanup in South Lake Tahoe.” said Executive Officer Patty Kouyoumdjian. Information obtained from the Lahontan Water Board’s questionnaires will be used to further refine its regional PCE groundwater contamination characterization study that is being conducted this summer with funding from a $4.6 million grant award issued by the State Water Resources Control Board’s Site Cleanup Subaccount Program.

PCE has been detected in recent groundwater samples as high as approximately 1,700 parts per billion (ppb) and in recent individual water supply well samples as high as an estimated 60 ppb. Any water wells with detections exceeding 5 ppb were shut down or treatment has been added to ensure customers continue receiving safe drinking water.

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