Johnson Reservoir
Dawson County, Montana32 acresView mapDirections
No nutrient or algae sampling on record from Montana DEQ for this lake.
Johnson Reservoir in Dawson County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Surface area: 32 acres.
Johnson Reservoir is a 32-acre lake in Dawson County, Montana.
Source: EPA Water Quality Portal sampling records, Montana DEQ. Methodology: how these readings are compared.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Johnson Reservoir is safe to swim in today is a call for the Montana Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Johnson Reservoir
These are the measurements Montana DEQ publishes for Johnson Reservoir, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. TSI undefined.
Ask about Johnson Reservoir
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
32 acres
No bathymetric survey has been published for Johnson Reservoir, so its depth is not documented here.
Stays via Stay22
Stays near Johnson Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Johnson Reservoir in Dawson County, Montana — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Johnson Reservoir
Prices for Oct 16–18, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Montana’s top lakes →
Follow Johnson Reservoir’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fishing Johnson Reservoir
Nearby Lakes in Dawson County
Frequently asked questions about Johnson Reservoir
Where is Johnson Reservoir?
- Johnson Reservoir is a lake in Dawson County, Montana. Its water-quality measurements are published by Montana DEQ and shown on this page as reported.
What is the water quality of Johnson Reservoir?
- Johnson Reservoir in Dawson County, Montana has water-quality measurements published by Montana DEQ, shown here as reported. Surface area: 32 acres.
Is Johnson Reservoir safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Explore Johnson Reservoir across LakeQuality
More lakes in Montana
Other Lakes in Montana
Where this data comes from
Measurements for Johnson Reservoir come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.