An update on microplastics in Lake Tahoe from the Tahoe Water Suppliers Association: 

Recent research published in, included Lake Tahoe among a global list of 38 freshwater lakes with high concentration of microplastics detected.

As part of ongoing watershed protection programs, the Tahoe Water Suppliers Association (TWSA) has worked in partnership with the Tahoe Environmental Research Center (TERC/UC Davis) and the Nevada Division of Environmental Protection (NDEP) to pro-actively study the presence of microplastics in the surface waters of Lake Tahoe.

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Tahoe Water Suppliers Association

To Sink or Swim: A Snapshot Evaluation of the Fate and Types of Microplastics in Lake Tahoe; published in 2023, by UC Davis Tahoe Environmental Research Center researcher, Katie Senft and associates, examined Lake Tahoe water sampled at six different depths from top to bottom.

Part of the sampling included a drinking water intake specific study. This study consisted of eight sampling events of two municipal drinking water sources in Lake Tahoe from summer 2021 to winter 2022. Samples were taken from the North Shore of Lake Tahoe at the Incline Village Improvement District and the South Shore at Edgewood Water Company. Click here for a detailed description of the project and the project sample sites.

This information yielded an average microplastic abundance of 0.044 particles/L, which points to minimal exposure to microplastics at Tahoe drinking water sources. The association members continue to be keenly aware of and closely following the science of microplastics and the monitoring protocols. They have been actively engaged in removing plastics and preventing more plastics from entering the watershed through public education and awareness efforts. They have determined this to be the best tool to alleviate accumulation of microplastics in the environment.

The municipal water samples collected consisted of two particles of polypropylene and one particle of polyester in 68.44 liters (L) of water.

What this means for Tahoe Tap drinkers is:

  • One microplastic particle detected per 23 liters of water (0.044 particles/L)
  • Possible ingestion of 1 microplastic particle every 7 days (based on average consumption) To compare, an average single-use plastic water bottle particle count is 94 particles/L.

“Bottled water is marketed as though it’s cleaner than tap, but regulatory reports and many studies show it’s definitely not cleaner,” TWSA Executive Director, Madonna Dunbar, stated. “Looking at the data, you’re going to be drinking significantly less plastic from tap water out of a glass than if you go and buy bottled water”.

If you are concerned about consuming microplastics – drinking Tahoe Tap from a glass or refillable bottle remains the best choice compared to plastic single-use bottles.

Some actions you can take to help prevent further microplastics in your drinking water include:

  • say no to single-use plastics whenever possible,
  • ‘pack it in – pack it out’ when visiting Lake Tahoe beaches,
  • refill your water bottle with Tahoe Tap,
  • use a water filter if you still have concerns,
  • volunteer for litter clean up and focus your efforts on plastics smaller than a bottle cap

Beginning in 2023, water suppliers within the TWSA will begin mandatory water sample collections in compliance with the Fifth Unregulated Contaminant Monitoring Rule (URCM 5) established by the U.S. Environmental Protection Agency (EPA). URCM 5 requires nationwide monitoring for 29 per- and polyfluoroalkyl substances (PFAS) and lithium in public drinking water systems from 2023 – 2025. Microplastics, such as polytetrafluorethylene used as nonstick coating on cooking pans, can be composed of PFAS meaning they will be monitored in the municipal waters of Lake Tahoe under URCM 5.

For more information on TWSA watershed protection projects and drinking water quality, please visit our website at

TWSA Members: Cave Rock Water System, Edgewood Water Company, Glenbrook Water Cooperative, Incline Village GID, Kingsbury GID, Lakeside Park Association, North Tahoe PUD, Round Hill GID, Skyland Water Company, South Tahoe PUD, Tahoe City PUD, Zephyr Water Utility

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