Warren Lake-Deep Spot
Warren Lake-Deep Spot in Cheshire County, New Hampshire has a water quality grade of C (Fair). Phosphorus: 16.8 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Surface area: 200 acres.
- Area
- 200 acres
- Type
- Eutrophic
Warren Lake-Deep Spot is a 200-acre productive, nutrient-rich eutrophic lake in Cheshire County, New Hampshire. Water quality is graded C based on 2 sampling years through 2025. Compared to the 37 other monitored lakes in Cheshire County, Warren Lake-Deep Spot ranks #29 for water quality.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-09-02. Grade methodology: LakeGrade methodology.
Watch Warren Lake-Deep Spot water quality
Subscribe for LakeQuality updates by email. No spam, unsubscribe anytime.
Swimming Safety
Grade onlyModerate
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.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
No clarity data. Phosphorus level: 16.8 µg/L. Chlorophyll-a: 7.6 µg/L. Trophic State Index: 48.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 16.8 µg/L | Fair |
| Chlorophyll-a (Algae) | 7.6 µg/L | Fair |
| Trophic State Index (TSI) | 48 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Warren Lake-Deep Spot
Compare lakeside cabins, hotels, and vacation rentals near Warren Lake-Deep Spot in Cheshire 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 Warren Lake-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 | 200 acres |
No bathymetric survey has been published for Warren Lake-Deep Spot, so its depth is not documented here.
Fishing Warren Lake-Deep Spot
Reservoir Info (USACE NID)
Warren Lake-Deep Spot is a man-made reservoir impounded by the Warren Lake Dam (completed 1771), built primarily for recreation on the Warren Brook; rockfill-type dam, 13 ft tall and 170 ft long.
- Surface area
- 200 ac
- Normal storage
- 501 ac-ft
- Max storage
- 1,739 ac-ft
- Drainage area
- 4.88 sq mi
- Hazard class
- High
- Owner
- TOWN OF ALSTEAD
Source: USACE National Inventory of Dams, NID ID NH00008 · Operator website · Matched by proximity (0.95 km)
EPA Impairment Status
Warren Lake-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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit NHLAK801070203-01 · Official waterbody report · Matched by proximity (0.24 km)
County Ranking
Ranked #29 of 38 lakes in Cheshire County
Nearby Lakes in Cheshire County
Frequently asked questions about Warren Lake-Deep Spot
Where is Warren Lake-Deep Spot?
- Warren Lake-Deep Spot is a lake in Cheshire County, New Hampshire. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Warren Lake-Deep Spot?
- Warren Lake-Deep Spot in Cheshire County, New Hampshire has a water quality grade of C (Fair). Phosphorus: 16.8 µg/L. Chlorophyll-a (algae): 7.6 µg/L. Surface area: 200 acres.
Is Warren Lake-Deep Spot safe to swim in?
- Generally safe for swimming, moderate water quality. Warren Lake-Deep Spot has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 7.6 µg/L. Always check local health department advisories before swimming.
Explore Warren Lake-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 C Lakes in New Hampshire
Eutrophic Lakes in New Hampshire
Where this data comes from
31 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)
1111330031 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