Dorrs Pond-Deep Spot
Hillsborough County, New Hampshire25 acresView mapDirections
NHDES publishes the water-quality measurements for Dorrs Pond-Deep Spot. Here is what has been measured.
- Eutrophic
- Impaired · Algal growth
- Public access
Dorrs Pond-Deep Spot in Hillsborough County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 27.7 µg/L. Chlorophyll-a (algae): 13.3 µg/L. Surface area: 25 acres.
Dorrs Pond-Deep Spot is a 25-acre productive, nutrient-rich eutrophic lake in Hillsborough County, New Hampshire. Limited fish-species data available. Public access is available. Compared to the 35 other monitored lakes in Hillsborough County, Dorrs Pond-Deep Spot ranks #32 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-08-27. Methodology: how these readings are compared.
Swimming conditions
Readings onlyRecreation 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. Dorrs Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen), oxygen depletion (low DO), salinity / chlorides. Check local advisories before you swim.
Whether Dorrs 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.
Water quality measurements for Dorrs Pond-Deep Spot
These are the measurements NHDES publishes for Dorrs 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 27.7 µg/L. Chlorophyll-a 13.3 µg/L. TSI 54.
| 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 | 27.7µg/L | Fair GoodFairPoor |
| Chlorophyll-a (algae) | 13.3µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 54 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Dorrs Pond-Deep Spot
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
25 acres
Public access
Yes
Listed by NHDES
No bathymetric survey has been published for Dorrs Pond-Deep Spot, so its depth is not documented here.
Stays via Stay22
Stays near Dorrs Pond-Deep Spot
Compare lakeside cabins, hotels, and vacation rentals near Dorrs Pond-Deep Spot in Hillsborough 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Dorrs Pond-Deep Spot are listed below.
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Fishing Dorrs Pond-Deep Spot
Reservoir Info (USACE NID)
Dorrs Pond-Deep Spot is a man-made reservoir impounded by the Dorrs Pond Dam (completed 1934), built primarily for recreation on the Dorrs Pond; earth-type dam, 9 ft tall and 125 ft long.
- Surface area
- 25 ac
- Normal storage
- 60 ac-ft
- Max storage
- 118 ac-ft
- Drainage area
- 2.4 sq mi
- Hazard class
- High
- Owner
- CITY OF MANCHESTER
Source: USACE National Inventory of Dams, NID ID NH00518 · Operator website · Matched by proximity (0.16 km)
EPA Impairment Status
Dorrs Pond-Deep Spot is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Aquatic life, Fish consumption, Recreation.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700060802-01 · Official waterbody report
Nearby Lakes in Hillsborough County
Frequently asked questions about Dorrs Pond-Deep Spot
Where is Dorrs Pond-Deep Spot?
- Dorrs Pond-Deep Spot is a lake in Hillsborough County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Dorrs Pond-Deep Spot?
- Dorrs Pond-Deep Spot in Hillsborough County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 27.7 µg/L. Chlorophyll-a (algae): 13.3 µg/L. Surface area: 25 acres.
Is Dorrs Pond-Deep Spot safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Dorrs Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 5) for algal growth, mercury, nutrients (phosphorus, nitrogen), oxygen depletion (low DO), salinity / chlorides. Check local advisories before you swim.
Can I fish at Dorrs Pond-Deep Spot?
- Public access to Dorrs Pond-Deep Spot 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.
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Where this data comes from
25 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
1111330025 samples · 2020–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
- CHLOROPHYLL A-B-C DETERMINATION (MODIFIED)
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