Flathead Lake Swim Guide
Monitoring the water quality of Flathead Lake’s swimming beaches
Flathead Lake’s swimming areas are exceptionally clean.
Water at Flathead Lake's beaches are monitored for recreational water quality during the swimming season:
July 10th through September 12th.
The Swim Guide
The Flathead Lakers have been involved in the Swim Guide since its introduction to Flathead Lake in 2018, by open water swimmer and coach Mark Johnston of FLOW Swimmers. We sample and monitor the water quality of Flathead Lake’s swimming beaches to reduce the risk of water-borne illnesses due to open water swimming
The Flathead Swim Guide Project is a collaborative project between the Flathead Lakers, Flathead Lake Biological Station (FLBS), and the Confederated Salish and Kootenai Tribes. We provide weekly updates on water quality for 16 swimming locations around Flathead Lake.
You can find the locations and results for each beach at The Swim Guide, or download the app for iOS or Android. The Swim Guide provides information on over 7000 swimming locations throughout the world.
The Flathead Lake Biological Station supports the Swim Guide by testing the water samples taken from local swim beaches,