Riverside Park - Flathead Lake

Polson, Montana

Our recreational water quality monitoring program is complete for the season. Please note that our beaches passed 95% of the tests this summer. For the most up to date water quality information from around the world, download the free app at www.TheSwimGuide.org. Water conditions can change quickly, so always use caution.

Thanks to Eric and Amber at Riverside Rec for their continued adoption of Riverside Park in Polson. Situated right beside the park to the south, Riverside Rec is the best place in town to rent ALL your water toys for summer: boats, SUPs, jet skis, and EVERYTHING fun is ready for your stay on Flathead Lake. Visit www.riversiderec.com for more information.

Thanks to Flathead Lake RV and Riverside Recreation for adopting Riverside Park and Salish Point for the summer of 2019!

Flathead RV is the premier RV park in the valley and is located just to the west of the Polson bridge. Riverside Recreation, located adjacent to Riverside Park, serves all your boat rental and water recreation needs.

Our water quality monitoring for 2019 will begin on June 26th. Stay tuned for updates on the recreational water quality and current water temperature for this beach soon.

Flathead Lake in northwest Montana is the largest natural freshwater lake west of the Mississippi; slightly larger than Lake Tahoe at 27.3 mi. long, 15.5 mi. wide, and max depth of 370.7 ft.

As one of the cleanest in the world, Flathead Lake is perfect for OPEN WATER SWIMMING! No sharks, no jellyfish, and no lane lanes...just clear, clean, and crisp water!

Riverside Park is located on the southern shore of Flathead Lake in Polson MT just south of the Memorial Bridge over the mouth of the Flathead River.

In addition to a roped off swimming area between two docks, this park is a great place for the entire family with a children's playground and a LARGE lawn area.

Unless you like your water COLD, the effective swimming season is June through September. Average water temps in June are in the 60s, 70s in July and August, and then back down again in September.

Summer air temperatures average in the mid-70s to mid-80s.

While no concessions are available in the park, downtown Polson is nearby with a few nice restaurants and great summer fare.

Bathrooms are available and parking is easy.

Swim Guide shares the best information we have at the moment you ask for it. Always obey signs at the beach or advisories from official government agencies. Stay alert and check for other swimming hazards such as dangerous currents and tides. Please report your pollution concerns so Affiliates can help keep other beach-goers safe.

Beach conditions change constantly, and it is never wise to swim in open water up to 48-hours after a heavy rain. Please use caution!

COVID-19

Keep your distance from other people.

Practicing social distancing is still essential. Only go to the beach if you are able to keep 6 feet or 2 meters away from others. Follow the instructions provided by your local health authorities. If your community has asked that you remain indoors and away from others, do so. Spending a day in any crowded place is the worst thing we can do for our most vulnerable right now and will counter our efforts to curb the virus’s spread.

Water Quality
  • Passed water quality tests 60-95% of the time

  • Historical Status
  • This status is based on the latest sample, taken on August 31st, 2021. Flathead Lake Open Water Swimmers updates the status of this beach as soon as test results become available. These results were posted to Swim Guide on August 31st, 2021 at 6:09 PM.
For water quality icon legend, click:  
Monitoring Frequency

Riverside Park - Flathead Lake is sampled weekly from June 26th to August 28th.

Source Information

Flathead Lake in northwest Montana is the largest natural freshwater lake west of the Mississippi; slightly larger than Lake Tahoe at 27.3 mi. long, 15.5 mi. wide, and max depth of 370.7 ft.. As one of the cleanest in the world, Flathead Lake is perfect for OPEN WATER SWIMMING! No sharks, no jellyfish, and no lane lanes, just clear, clean, and crisp water!

Water at Flathead Lake's bathing beaches is monitored for recreational water quality during effective swimming season: July 1st through September 1st.


In 2017 FLOW Swimmers (Flathead Lake Open Water Swimmers) launched a sampling program of three local beaches. In 2018, the program has grown to 10 beaches around the lake. Samples areprocessed by Flathead Lake Biological Research Station. The water at the bathing beaches will be tested for E.coli


Monitoring Status
Montana follows federal guidelines for the monitoring of its recreational waters.
The guidelines for freshwater levels of E. coli are a geometric mean of 100 cfu per 100 mL and an STV of 320 cfu per 100 mL, measured using EPA Method 1603, or any other equivalent method that measures culturable E. coli.

E. coli
A beach is marked Green when two consecutive single sample results are under a geometric mean of 100 cfu per 100 mL and an STV of 320 cfu per 100 mL


A beach is marked Red when two consecutive single sample results are equal to or above a geometric mean of 100 cfu per 100 mL or aSTV of 320 cfu per 100 mL


A beach is marked Grey if there is no current results or no available information.

Read more
Water Quality Graph

Riverside Park - Flathead Lake

Polson, Montana

COVID-19

Keep your distance from other people.

Practicing social distancing is still essential. Only go to the beach if you are able to keep 6 feet or 2 meters away from others. Follow the instructions provided by your local health authorities. If your community has asked that you remain indoors and away from others, do so. Spending a day in any crowded place is the worst thing we can do for our most vulnerable right now and will counter our efforts to curb the virus’s spread.

Water Quality
  • Passed water quality tests 60-95% of the time
  • Historical Status
  • This status is based on the latest sample, taken on August 31st, 2021. Flathead Lake Open Water Swimmers updates the status of this beach as soon as test results become available. These results were posted to Swim Guide on August 31st, 2021 at 6:09 PM.
For water quality icon legend, click:  

Our recreational water quality monitoring program is complete for the season. Please note that our beaches passed 95% of the tests this summer. For the most up to date water quality information from around the world, download the free app at www.TheSwimGuide.org. Water conditions can change quickly, so always use caution.

Thanks to Eric and Amber at Riverside Rec for their continued adoption of Riverside Park in Polson. Situated right beside the park to the south, Riverside Rec is the best place in town to rent ALL your water toys for summer: boats, SUPs, jet skis, and EVERYTHING fun is ready for your stay on Flathead Lake. Visit www.riversiderec.com for more information.

Thanks to Flathead Lake RV and Riverside Recreation for adopting Riverside Park and Salish Point for the summer of 2019!

Flathead RV is the premier RV park in the valley and is located just to the west of the Polson bridge. Riverside Recreation, located adjacent to Riverside Park, serves all your boat rental and water recreation needs.

Our water quality monitoring for 2019 will begin on June 26th. Stay tuned for updates on the recreational water quality and current water temperature for this beach soon.

Flathead Lake in northwest Montana is the largest natural freshwater lake west of the Mississippi; slightly larger than Lake Tahoe at 27.3 mi. long, 15.5 mi. wide, and max depth of 370.7 ft.

As one of the cleanest in the world, Flathead Lake is perfect for OPEN WATER SWIMMING! No sharks, no jellyfish, and no lane lanes...just clear, clean, and crisp water!

Riverside Park is located on the southern shore of Flathead Lake in Polson MT just south of the Memorial Bridge over the mouth of the Flathead River.

In addition to a roped off swimming area between two docks, this park is a great place for the entire family with a children's playground and a LARGE lawn area.

Unless you like your water COLD, the effective swimming season is June through September. Average water temps in June are in the 60s, 70s in July and August, and then back down again in September.

Summer air temperatures average in the mid-70s to mid-80s.

While no concessions are available in the park, downtown Polson is nearby with a few nice restaurants and great summer fare.

Bathrooms are available and parking is easy.

Swim Guide shares the best information we have at the moment you ask for it. Always obey signs at the beach or advisories from official government agencies. Stay alert and check for other swimming hazards such as dangerous currents and tides. Please report your pollution concerns so Affiliates can help keep other beach-goers safe.

Beach conditions change constantly, and it is never wise to swim in open water up to 48-hours after a heavy rain. Please use caution!

Monitoring Frequency

Riverside Park - Flathead Lake is sampled weekly from June 26th to August 28th.

Source Information

Flathead Lake in northwest Montana is the largest natural freshwater lake west of the Mississippi; slightly larger than Lake Tahoe at 27.3 mi. long, 15.5 mi. wide, and max depth of 370.7 ft.. As one of the cleanest in the world, Flathead Lake is perfect for OPEN WATER SWIMMING! No sharks, no jellyfish, and no lane lanes, just clear, clean, and crisp water!

Water at Flathead Lake's bathing beaches is monitored for recreational water quality during effective swimming season: July 1st through September 1st.


In 2017 FLOW Swimmers (Flathead Lake Open Water Swimmers) launched a sampling program of three local beaches. In 2018, the program has grown to 10 beaches around the lake. Samples areprocessed by Flathead Lake Biological Research Station. The water at the bathing beaches will be tested for E.coli


Monitoring Status
Montana follows federal guidelines for the monitoring of its recreational waters.
The guidelines for freshwater levels of E. coli are a geometric mean of 100 cfu per 100 mL and an STV of 320 cfu per 100 mL, measured using EPA Method 1603, or any other equivalent method that measures culturable E. coli.

E. coli
A beach is marked Green when two consecutive single sample results are under a geometric mean of 100 cfu per 100 mL and an STV of 320 cfu per 100 mL


A beach is marked Red when two consecutive single sample results are equal to or above a geometric mean of 100 cfu per 100 mL or aSTV of 320 cfu per 100 mL


A beach is marked Grey if there is no current results or no available information.

Read more
Water Quality Graph

  Beach Location Water Quality
Polson, Montana
Polson, Montana
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Swim Guide
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Swim Guide shares the best information we have at the moment you ask for it. Always obey signs at the beach or advisories from official government agencies. Stay alert and check for other swimming hazards such as dangerous currents and tides. Please report your pollution concerns so Affiliates can help keep other beach-goers safe.

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