Where is Tom Pond-Deep Spot?

Tom Pond-Deep Spot is a lake in Merrimack County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.

Tom Pond-Deep Spot

Merrimack County, New HampshireView map Directions

NHDES publishes the water-quality measurements for Tom Pond-Deep Spot. Here is what has been measured.

Phosphorus

13.1 µg/L

Typical for New Hampshire

Measured by NHDES

Chlorophyll-a

7.8 µg/L

More algae than most

Measured by NHDES

Type

Eutrophic

Trophic class

Eutrophic
Impaired · Algal growth

See the measurements Directions Where to stay

Tom Pond-Deep Spot in Merrimack County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 13.1 µg/L. Chlorophyll-a (algae): 7.8 µg/L.

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Tom Pond-Deep Spot is a productive, nutrient-rich eutrophic lake in Merrimack County, New Hampshire. Compared to the 40 other monitored lakes in Merrimack County, Tom Pond-Deep Spot ranks #34 for water quality.

Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-08-18. Methodology: how these readings are compared.

Swimming conditions

Readings only

Recreation use not supported

Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.

Nutrient and algae readings are not a swimming clearance. Tom Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 4A) for algal growth, mercury, nutrients (phosphorus, nitrogen), pH / acidity. Check local advisories before you swim.

Whether Tom Pond-Deep Spot 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 Tom Pond-Deep Spot

These are the measurements NHDES publishes for Tom Pond-Deep Spot, 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 13.1 µg/L. Chlorophyll-a 7.8 µg/L. TSI 46.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)		No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	13.1µg/L	Good GoodFairPoor
Chlorophyll-a (algae)	7.8µg/L	Fair GoodFairPoor
Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a.	46	Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic

High nutrients, frequent algae, reduced clarity

Ask about Tom Pond-Deep Spot

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

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Stays near Tom Pond-Deep Spot

Compare lakeside cabins, hotels, and vacation rentals near Tom Pond-Deep Spot in Merrimack County, New Hampshire — 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 Tom Pond-Deep Spot

→ Tom Pond-Deep Spot fishing regulations (limits, seasons, special rules)

EPA Impairment Status

Tom Pond-Deep Spot is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Algal growthMercuryNutrients (phosphorus, nitrogen)pH / acidity

Designated uses not supporting: Aquatic life, Fish consumption, Recreation.

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

Source: EPA ATTAINS assessment unit NHLAK700030304-05 · Official waterbody report

Nearby Lakes in Merrimack County

Clement Pond-Deep SpotMesotrophic2.4 miView →Grassy Pond—View →Trumbull Pond—View →Rolf Pond-Deep Spot3.2 miView →Bear Pond—View →Lake Winnepocket-End of Lake Inlet3.7 miView →

Frequently asked questions about Tom Pond-Deep Spot

Where is Tom Pond-Deep Spot?: Tom Pond-Deep Spot 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 Tom Pond-Deep Spot?: Tom Pond-Deep Spot in Merrimack County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 13.1 µg/L. Chlorophyll-a (algae): 7.8 µg/L.
Is Tom Pond-Deep Spot safe to swim in?: Nutrient and algae readings are not a swimming clearance. Tom Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 4A) for algal growth, mercury, nutrients (phosphorus, nitrogen), pH / acidity. Check local advisories before you swim.

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