Tower Hill Pond-Deep Spot
Rockingham County, New Hampshire202 acresView mapDirections
NHDES publishes the water-quality measurements for Tower Hill Pond-Deep Spot. Here is what has been measured.
- Mesotrophic
- Impaired · Mercury
- Public access
- Limited data
Tower Hill Pond-Deep Spot in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 17.6 µg/L. Surface area: 202 acres.
Tower Hill Pond-Deep Spot is a 202-acre mesotrophic lake in Rockingham County, New Hampshire. Limited fish-species data available. Public access is available. Compared to the 50 other monitored lakes in Rockingham County, Tower Hill Pond-Deep Spot ranks #43 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-07-15. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
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. Tower Hill Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Tower Hill 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 Tower Hill Pond-Deep Spot
These are the measurements NHDES publishes for Tower Hill 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 17.6 µg/L. TSI 46.
| 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 | 17.6µg/L | Fair GoodFairPoor |
| 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. | 46 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
Ask about Tower Hill Pond-Deep Spot
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
202 acres
Public access
Yes
Listed by NHDES
No bathymetric survey has been published for Tower Hill Pond-Deep Spot, so its depth is not documented here.
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Fishing Tower Hill Pond-Deep Spot
Reservoir Info (USACE NID)
Tower Hill Pond-Deep Spot is a man-made reservoir impounded by the Tower Hill Pond Dam (completed 1938), built primarily for water supply on the Maple Falls Brook; earth-type dam, 35 ft tall and 1,220 ft long.
- Surface area
- 202 ac
- Normal storage
- 3,960 ac-ft
- Max storage
- 5,020 ac-ft
- Drainage area
- 12.5 sq mi
- Hazard class
- High
- Owner
- MANCHESTER WATER WORKS
Source: USACE National Inventory of Dams, NID ID NH00219 · Operator website · Matched by proximity (0.29 km)
EPA Impairment Status
Tower Hill 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
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700060701-04 · Official waterbody report
Nearby Lakes in Rockingham County
Frequently asked questions about Tower Hill Pond-Deep Spot
Where is Tower Hill Pond-Deep Spot?
- Tower Hill Pond-Deep Spot is a lake in Rockingham County, New Hampshire. Its water-quality measurements are published by NHDES and shown on this page as reported.
What is the water quality of Tower Hill Pond-Deep Spot?
- Tower Hill Pond-Deep Spot in Rockingham County, New Hampshire has water-quality measurements published by NHDES, shown here as reported. Phosphorus: 17.6 µg/L. Surface area: 202 acres.
Is Tower Hill Pond-Deep Spot safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Tower Hill Pond-Deep Spot is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Can I fish at Tower Hill Pond-Deep Spot?
- Public access to Tower Hill 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
7 measurements from 1 monitoring station, 2024–2025. Retrieved from the EPA Water Quality Portal on 2026-08-21.
Collected and reported by
- New Hampshire Department Of Environmental Services (BEACH)
111133007 samples · 2024–2025
Analytical methods
- 10-115-01-1 F ~ LACHAT; Total Phosphorus- Manual persulfate digest
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