Lost Lake is a lake in Middlesex County, Massachusetts. Its water-quality measurements are published by MassDEP and shown on this page as reported.

Lost Lake

Middlesex County, Massachusetts122 acresView map Directions

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

Area

122 acres

Surface area

Shoreline

4.4 mi

Measured length

Impaired · Algal growth

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Lost Lake in Middlesex County, Massachusetts has water-quality measurements published by MassDEP, shown here as reported. Surface area: 122 acres.

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Lost Lake is a 122-acre lake in Middlesex County, Massachusetts.

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

Swimming conditions

No reading

Not rated

Nutrient and algae readings are not a swimming clearance. Lost Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for algal growth, mercury, nuisance exotic species. Check local advisories before you swim.

Whether Lost Lake is safe to swim in today is a call for the Massachusetts Department of Environmental Protection and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Lost Lake

These are the measurements MassDEP publishes for Lost Lake, 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 Lost Lake

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

Lake Details

Surface area

122 acres

Shoreline

4.4 mi

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

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Stays near Lost Lake

Compare lakeside cabins, hotels, and vacation rentals near Lost Lake in Middlesex County, Massachusetts — 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.

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Fishing Lost Lake

→ Lost Lake fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Lost Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).

Causes of impairment

Algal growthMercuryNuisance exotic species

Designated uses not supporting: Aquatic life, Fish consumption.

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MA84084 · Official waterbody report

Nearby Lakes in Middlesex County

Knops Pond0.5 miView →Whitney Pond0.9 miView →Baddacook Pond1.7 miView →Long Pond2 miView →Spectacle Pond2.3 miView →Forge Pond2.3 miView →

Frequently asked questions about Lost Lake

Where is Lost Lake?: Lost Lake is a lake in Middlesex County, Massachusetts. Its water-quality measurements are published by MassDEP and shown on this page as reported.
What is the water quality of Lost Lake?: Lost Lake in Middlesex County, Massachusetts has water-quality measurements published by MassDEP, shown here as reported. Surface area: 122 acres.
Is Lost Lake safe to swim in?: Nutrient and algae readings are not a swimming clearance. Lost Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for algal growth, mercury, nuisance exotic species. Check local advisories before you swim.