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LakeQuality

Stinson Lake-Near Outlet

Grafton County, New Hampshire344 acresView mapDirections

This is the name NHDES records for this water. It can describe one sampling location rather than the water as a whole.

NHDES publishes the water-quality measurements for Stinson Lake-Near Outlet. Here is what has been measured.

Phosphorus
5.2 µg/L
Less phosphorus than most
Measured by NHDES
Area
344 acres
Surface area
  • Impaired · Mercury
  • Public access
  • Limited data

Stinson Lake-Near Outlet in Grafton County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 5.2 µg/L. Surface area: 344 acres.

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Stinson Lake-Near Outlet is a 344-acre lake in Grafton County, New Hampshire. Limited fish-species data available. Public access is available.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2021-07-05. Methodology: how these readings are compared.

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Stinson Lake-Near Outlet is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), pH / acidity. Check local advisories before you swim.

Whether Stinson Lake-Near Outlet 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.

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Water quality measurements for Stinson Lake-Near Outlet

These are the measurements NHDES publishes for Stinson Lake-Near Outlet, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

No clarity data. Phosphorus 5.2 µg/L. TSI 28.

Water quality readings
MeasureReadingWhere it sits
Water clarity (Secchi depth)No reading

How deep a black-and-white disk stays visible from the surface. Higher is clearer.

Total phosphorus5.2µg/LMeasured, not scored

The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.

Chlorophyll-a (algae)No reading

The green pigment in algae — a direct measure of how much algae is in the water.

Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a.28Oligotrophic
OligotrophicMesotrophicEutrophicHypereutrophic

Low nutrients, clear water. No reading is a swimming clearance.

Ask about Stinson Lake-Near Outlet

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

Lake Details

Surface area

344 acres

Public access

Yes

Listed by NHDES

No bathymetric survey has been published for Stinson Lake-Near Outlet, so its depth is not documented here.

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Fishing Stinson Lake-Near Outlet

Reservoir Info (USACE NID)

Stinson Lake-Near Outlet is a man-made reservoir impounded by the Stinson Lake Dam (completed 1780), built primarily for recreation on the Stinson Brook; earth-type dam, 8 ft tall and 158 ft long.

Surface area
344 ac
Normal storage
459 ac-ft
Max storage
1,890 ac-ft
Drainage area
7.83 sq mi
Hazard class
Low
Owner
NH DES WATER DIVISION

Source: USACE National Inventory of Dams, NID ID NH00399 · Operator website · Matched by proximity (0.06 km)

EPA Impairment Status

Stinson Lake-Near Outlet is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

MercuryMetals (other than mercury)pH / acidity

Designated uses not supporting: Aquatic life, Fish consumption.

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

Source: EPA ATTAINS assessment unit NHLAK700010306-01 · Official waterbody report

Nearby Lakes in Grafton County

Frequently asked questions about Stinson Lake-Near Outlet

Where is Stinson Lake-Near Outlet?

Stinson Lake-Near Outlet is in Grafton County, New Hampshire. This is the name NHDES records for this water. It can describe one sampling location rather than the water as a whole. Its water-quality measurements are published by NHDES and shown on this page as reported.

What is the water quality of Stinson Lake-Near Outlet?

Stinson Lake-Near Outlet in Grafton County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 5.2 µg/L. Surface area: 344 acres.

Measurements on this page ↑

Is Stinson Lake-Near Outlet safe to swim in?

Nutrient and algae readings are not a swimming clearance. Stinson Lake-Near Outlet is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, metals (other than mercury), pH / acidity. Check local advisories before you swim.

Swimming on this page ↑

Can I fish at Stinson Lake-Near Outlet?

Public access to Stinson Lake-Near Outlet is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by New Hampshire's fish and wildlife agency, so check its current regulations before you go.

Where this data comes from

3 measurements from 1 monitoring station, 2020–2021. Retrieved from the EPA Water Quality Portal on 2026-08-21.

Collected and reported by

  • New Hampshire Department Of Environmental Services (BEACH)111133003 samples · 2020–2021

Analytical methods

  • 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
  • 2130 B ~ Nephelometric Method
Monitoring station identifiers (1)

EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database