The Flathead Swim Guide Project is a collaborative project between the Flathead Lakers, Monitoring Montana Waters, and the Confederated Salish and Kootenai Tribes. The Flathead Lake Swim Guide program monitors E. coli levels at sixteen public swimming areas throughout the summer swimming season from July through September.  

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. Johnston observed that while many U.S. recreational waters were routinely tested for safety, Flathead Lake lacked such a program. Concerned about potential health risks for local swimmers, he initiated water quality monitoring at popular swim areas around the lake.  He partnered with Monitoring Montana Waters in 2021, and the Flathead Lakers took on program management in 2022. Now in 2025, the program is entering into its eighth season of monitoring. 

Consistent monitoring allows for early detection of issues and helps protect public health. 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 is a global platform that provides water quality data for more than 8,000 beaches worldwide. The Flathead Lakers upload their results to The Swim Guide platform each week. Water quality samples are analyzed at the Flathead Lake Biological Station Freshwater Research Lab.