Pratt Pond-Deep Spot
Pratt Pond-Deep Spot in Hillsborough County, New Hampshire has a water quality grade of B (Good). Phosphorus: 10.7 µg/L. Chlorophyll-a (algae): 8.2 µg/L. Surface area: 35 acres.
- Area
- 35 acres
- Type
- Mesotrophic
Pratt Pond-Deep Spot is a 35-acre mesotrophic lake in Hillsborough County, New Hampshire. Water quality is graded B based on 1 sampling years through 2025. Compared to the 35 other monitored lakes in Hillsborough County, Pratt Pond-Deep Spot ranks #9 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-08-04. Grade methodology: LakeGrade methodology.
Watch Pratt Pond-Deep Spot water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
No clarity data. Phosphorus level: 10.7 µg/L. Chlorophyll-a: 8.2 µg/L. Trophic State Index: 45.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 10.7 µg/L | Good |
| Chlorophyll-a (Algae) | 8.2 µg/L | Not graded |
| Trophic State Index (TSI) | 45 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Pratt Pond-Deep Spot
Compare lakeside cabins, hotels, and vacation rentals near Pratt 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.
Top-rated places to stay near Pratt Pond-Deep Spot
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 35 acres |
No bathymetric survey has been published for Pratt Pond-Deep Spot, so its depth is not documented here.
Fishing Pratt Pond-Deep Spot
Reservoir Info (USACE NID)
Pratt Pond-Deep Spot is a man-made reservoir impounded by the Pratt Pond Dam (completed 1890), built primarily for recreation on the Pratt Brook; earth-type dam, 7 ft tall and 150 ft long.
- Surface area
- 35 ac
- Normal storage
- 58 ac-ft
- Max storage
- 110 ac-ft
- Drainage area
- 0.74 sq mi
- Hazard class
- Low
- Owner
- PRATT POND ASSOCIATION
Source: USACE National Inventory of Dams, NID ID NH00557 · Operator website · Matched by proximity (0.6 km)
EPA Impairment Status
Pratt 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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK700060901-03 · Official waterbody report · Matched by proximity (0.23 km)
County Ranking
Ranked #9 of 36 lakes in Hillsborough County
Nearby Lakes in Hillsborough County
Frequently asked questions about Pratt Pond-Deep Spot
Where is Pratt Pond-Deep Spot?
- Pratt Pond-Deep Spot is a lake in Hillsborough County, New Hampshire. LakeQuality grades it B for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Pratt Pond-Deep Spot?
- Pratt Pond-Deep Spot in Hillsborough County, New Hampshire has a water quality grade of B (Good). Phosphorus: 10.7 µg/L. Chlorophyll-a (algae): 8.2 µg/L. Surface area: 35 acres.
Is Pratt Pond-Deep Spot safe to swim in?
- Good for swimming, clear water with low algae levels. Pratt Pond-Deep Spot has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 8.2 µg/L. Always check local health department advisories before swimming.
Explore Pratt Pond-Deep Spot across LakeGrade
More New Hampshire Lake Rankings
Top 25 by overall water quality score
Top 25 by Secchi water clarity
Grade A/B + low algae filter
Panfish-rich, public access
Full state directory
Other Grade B Lakes in New Hampshire
Mesotrophic Lakes in New Hampshire
Where this data comes from
8 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)
111133008 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)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database