Where is Grasmere Reservoir?

Grasmere Reservoir is a lake in Owyhee County, Idaho. Its water-quality measurements are published by Idaho DEQ and shown on this page as reported.

Grasmere Reservoir

Owyhee County, Idaho29 acresView map Directions

No nutrient or algae sampling on record from Idaho DEQ for this lake.

Area

29 acres

Surface area

Shoreline

1.1 mi

Measured length

Impaired · Mercury

See the measurements Directions Where to stay

Grasmere Reservoir in Owyhee County, Idaho has water-quality measurements published by Idaho DEQ, shown here as reported. Surface area: 29 acres.

Loading map…

Grasmere Reservoir is a 29-acre lake in Owyhee County, Idaho.

Source: EPA Water Quality Portal sampling records, IDEQ. Methodology: how these readings are compared.

Swimming conditions

No reading

Recreation use not supported

Nutrient and algae readings are not a swimming clearance. Grasmere Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.

Whether Grasmere Reservoir is safe to swim in today is a call for the Idaho Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

Get alerts for Grasmere Reservoir →

Water quality measurements for Grasmere Reservoir

These are the measurements Idaho DEQ publishes for Grasmere 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 Grasmere Reservoir

Answers come straight from the public measurements and survey records on this page.

Lake Details

Surface area

29 acres

Shoreline

1.1 mi

No bathymetric survey has been published for Grasmere Reservoir, so its depth is not documented here.

Stays via Stay22

Stays near Grasmere Reservoir

Compare lakeside cabins, hotels, and vacation rentals near Grasmere Reservoir in Owyhee County, Idaho — 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 Grasmere 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 Idaho’s top lakes →

Follow Grasmere Reservoir’s readings

Email me when new measurements post for this lake. Updates stay free.

Or email

Fishing Grasmere Reservoir

→ Grasmere Reservoir fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Grasmere Reservoir is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 5).

Causes of impairment

Mercury

Designated uses not supporting: Aquatic life, Recreation.

Source: EPA ATTAINS assessment unit ID17050102SW015_02L · Official waterbody report

Nearby Lakes in Owyhee County

Tindall Reservoir12.2 miView →Payne Creek Reservoir11.4 miView →Little Blue Creek Reservoir11.5 miView →Sage Hen Reservoir15 miView →Buckhorn Reservoir—View →Dry Lake16.7 miView →

Frequently asked questions about Grasmere Reservoir

Where is Grasmere Reservoir?: Grasmere Reservoir is a lake in Owyhee County, Idaho. Its water-quality measurements are published by Idaho DEQ and shown on this page as reported.
What is the water quality of Grasmere Reservoir?: Grasmere Reservoir in Owyhee County, Idaho has water-quality measurements published by Idaho DEQ, shown here as reported. Surface area: 29 acres.
Is Grasmere Reservoir safe to swim in?: Nutrient and algae readings are not a swimming clearance. Grasmere Reservoir is listed impaired under Clean Water Act §303(d) (IR 5) for mercury. Check local advisories before you swim.