Long Pond
Merrimack County, New Hampshire31 acresView mapDirections
No nutrient or algae sampling on record from NHDES for this lake.
- Impaired · Mercury
- 15 ft max depth
Long Pond in Merrimack County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Maximum depth: 15 ft. Surface area: 31 acres.
Long Pond is a 31-acre lake in Merrimack County, New Hampshire with a maximum depth of 15 feet (8-foot average).
Source: EPA Water Quality Portal sampling records, your state environmental agency. Methodology: how these readings are compared.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Long Pond is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, pH / acidity. Check local advisories before you swim.
Whether Long Pond is safe to swim in today is a call for the New Hampshire Department of Environmental Services and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Long Pond
These are the measurements NHDES publishes for Long Pond, 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 Long Pond
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
15 ft
Average depth
7.9 ft
Surface area
31 acres
Shoreline
1 mi
The depth above comes from a bathymetric survey of this lake, not from a regional estimate.
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Fishing Long Pond
EPA Impairment Status
Long Pond is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700060607-03 · Official waterbody report
Nearby Lakes in Merrimack County
Frequently asked questions about Long Pond
Where is Long Pond?
- Long Pond is a lake in Merrimack County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Long Pond?
- Long Pond in Merrimack County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Maximum depth: 15 ft. Surface area: 31 acres.
Is Long Pond safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Long Pond is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury, pH / acidity. Check local advisories before you swim.
How deep is Long Pond?
- Long Pond has a maximum depth of 15 feet and an average depth of 7.9 feet. The lake covers 31 acres.
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Where this data comes from
Measurements for Long Pond come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database